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Small basin hydrology in the discontinuous permafrost zone Vincent, David Guy 1979

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SMALL BASIN HYDROLOGY IN THE DISCONTINUOUS PERMAFROST 9 1 ZONE by DAVID GUY VINCENT B.A.Sc, University of B r i t i s h Columbia, 1975 A THESIS SUBMITTED IN PARTIAL FULFULLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES (Department of C i v i l Engineering) We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September, 19 7 9 (c) David Guy Vincent, 1979 In presenting this thesis in partial fulfilment o f the requirements f o r an advanced degree at the University of Brit ish C o l u m b i a , I ag ree t h a t the Library shall make it freely available for reference and study. I further agree that permission for extensive copying o f this thesis for scholarly purposes may be granted by the Head o f my Department o r by his representatives. It is understood that copying o r p u b l i c a t i o n o f this thesis for financial gain shall not be allowed without my written permission. Department of C \ V I L E M G l ^ £E"R.\^C; The University of Brit ish Columbia 2 0 7 5 W e s b r o o k P l a c e V a n c o u v e r , C a n a d a V 6 T 1W5 Date £>c i 12^  ABSTRACT The r e s p o n s e o f s m a l l n o r t h e r n b a s i n s t o s i m i l a r r a i n -f a l l e v e n t s c a n v a r y g r e a t l y due t o d r a m a t i c c h a n g e s w i t h t i m e i n b a s i n p a r a m e t e r s . An a t t e m p t i s made t o u n d e r s t a n d a n d q u a n t i f y t h e s e c h a n g e s a n d s u g g e s t i o n s t o i n c o r p o r a t e s y s t e m a t i c v a r i a t i o n i n m o d e l p a r a m e t e r s a r e made i n o r d e r t o p r o d u c e a m o r e r e l i a b l e ' n o r t h e r n ' m o d e l . Of p a r t i c u l a r i n t e r e s t a r e t h e p e r m a f r o s t r e g i m e , t h e v e g e t a t i v e c o v e r , t h e e v a p o r a t i o n p r o c e s s a n d t h e a t t e n u a t i o n o f t h e h y d r o g r a p h s m a k i n g a n t e c e -d e n t c o n d i t i o n s i m p o r t a n t i n p r e d i c t i n g p e a k f l o w s . F u r t h e r i d e a s a r e p r e s e n t e d t o p r o d u c e a d e t e r m i n i s t i c m o d e l w h i c h i n c o r p o r a t e s b o t h r a n d o m a n d s y s t e m a t i c c h a n g e s i n p a r a m e t e r s i n o r d e r t o y i e l d m o r e r e l i a b l e e s t i m a t e s o f f l o w s t a t i s t i c s f o r u s e i n d e s i g n . The b a c k g r o u n d s t u d y was s p o n s o r e d b y C a n a d i a n A r c t i c Gas S t u d y L i m i t e d d u r i n g t h e i r b i d t o c o n s t r u c t a p i p e l i n e i n t h e M a c k e n z i e V a l l e y . i i i TABLE OF CONTENTS Page Abstract i i Table of Contents i i i L i s t of Tables v L i s t of Figures v i Acknowledgements v i i CHAPTER I - INTRODUCTION 1 CHAPTER II - WHAT'S NORTH AND WHY 5 2.1 Permafrost 6 2.2 Vegetation & So i l s 10 2.3 Potential and Available Storage 13 2.4 The eff e c t s of Permafrost melt on the rate of runoff and Potential Storage 15 2.5 Evaporation 16 2.6 Surface Disturbance 20 CHAPTER III - THE CHICK LAKE STUDY 21 3.1 Background 21 3.2 The Study Area 21 3.3 Local Topography, Climate,Geology and Vegetation 22 3.4 Data Co l l e c t i o n History 27 3.5 Gage Sites 31 3.6 Chick Lake Study Basins 35 3.7 Chick Lake - Data Presentation & Analysis 36 i v CHAPTER IV - DATA PREPARATION AND ANALYSIS 39 4.1 The Next Step 44 CHAPTER V - CONCLUSIONS 49 BIBLIOGRAPHY 54 APPENDIX 56 V LIST OF TABLES Page I Calculation of Evaporation at Norman Wells, N.W.T., by Thornthwaite 1s method based on mean monthly data 17 II Mean Monthly Weather Cha r a c t e r i s t i c s , Norman Wells 25 & Fort Good Hope, N.W.T. 26 III Summary of Results 42 v i LIST OF FIGURES Figure Page 1 General Location Map 2 2 Depth to the f r o s t table 8 3 Typical Chick Lake S o i l P r o f i l e Data 12 4 Potential Storage 14 5 Evaporation at Norman Wells, N.W.T. 18 6 Cut-Away of Rain Gage Set-up 29 7 Typical Basin Arrangement of Chick Lake Sites 30 8 Chick Lake Site Map 34 9 19 77 R a i n f a l l & Runoff Data, Chick Lake 37 10 I n f i l t r a t i o n Rate vs I n i t i a l Loss 41 11 Investigation of trends i n summer storms at Norman Wells 4 6 v i i ACKNOWLEDGEMENTS The author i s grateful to Canadian A r c t i c Gas Study Limited for permission to publish data c o l l e c t e d at Chick Lake, and to the National Research Council for support during the university phase of the study. Special thanks are extended to Dr. S.O. Russell of U.B.C. and Mr. E.D. Soulis of S.I. Solomon and Associates for aid and d i r e c t i o n during the study. -1-1.0 INTRODUCTION While the permafrost regions of Canada constitute approximately one-half of the t o t a l land area of the country, very l i t t l e attention has been focused on t h i s vast area u n t i l recently. As a r e s u l t , r e l a t i v e l y l i t t l e experience and v i r t u a l l y no base data ex i s t to support the accelerated push of modern man into the vast regions of muskeg and perma-f r o s t . This dearth of experience and data i s p a r t i c u l a r l y apparent when dealing in. the area of hydrologic design includ-ing drainage, erosion and environmental impact, since disturb-ing the water regime of an area can have far reaching environmental implications. Part of the solution applied to bridge t h i s lack of information i s the hydrologic modelling approach. Unfortunately the methods developed i n southern regions often do not describe the northern environment well, r e s u l t i n g i n inappropriate designs. This thesis describes a preliminary examination of the hydrologic mechanisms under northern conditions, based on a study i n i t i a t e d by the Canadian A r c t i c Gas Study Limited during t h e i r bid to b u i l d a Mackenzie Valley Gas Pipeline. The study, at Chick Lake, N.W.T. (see Figure 1), set out to examine the summer hydrology of the muskeg/permafrost t e r r a i n type frequently encountered i n the north, p a r t i c u l a r l y i n the transportation corridor of the Mackenzie Valley. F i e l d work over a period of three years produced l i t t l e i n the way of 'hard' data, but from observations a great deal was learned about the processes involved and the i n t e r - r e l a t i o n of the vegetation, permafrost and water regime. The work entailed -2-F/GURE /: GENERAL LOCAT/O/V MAP - 3 -monitoring four small drainage basins, and c o r r e l a t i n g streamflows with r a i n f a l l data co l l e c t e d on s i t e . This data was to provide the basis for designing and c a l i b r a t i n g a suitable model for generating flood frequency data for s t r u c t u r a l design. The results showed that some serious inaccuracies could arise from the d i r e c t application i n northern areas of hydrologic techniques developed i n temperate regions. The main point i s that the basin (and thus the model) parameters change dramatically through the summer season. Further, since the surface layer storage i s large, hydrographs of even small basins are greatly attenuated and thus the assumption that independent r a i n f a l l events produce independent flood peaks of si m i l a r return periods i s generally i n v a l i d . F i n a l l y , the assumption that evaportation i s n e g l i g i b l e can be shown to be quite incorrect, and the process i s an important mechanism when attempting to model the regime to provide v a l i d flood frequency estimates. The muskeg and permafrost regions of northern Canada are fundamentally d i f f e r e n t from a hydrologic viewpoint from those i n the south. Over design can lead to as serious problems as can under design, since drainage of normally wet land w i l l cause changes i n the permafrost regime which i n turn can seriously disrupt the ecology of a large area, or the development being constructed. Unfortunately, a l l to often 'southern' techniques are transplanted d i r e c t l y north and the e f f e c t of the permafrost and muskeg on the water regime i s - 4 -ignored. A b r i e f survey conducted by Newbury (Newbury, 1974) indicated that a disturbing number of consultants and govern-ment departments with northern r e s p o n s i b i l i t i e s f a i l to recog-nize the importance of permafrost on the water regime, and furthermore, are not interested i n expanding t h e i r expertise in order to improve the quality..of design. Hopefully, t h i s p o t e n t i a l l y disastrous s i t u a t i o n i s gradually being r e c t i f i e d . This thesis i s broken into four somewhat overlapping sections plus an appendix. The f i r s t section presents terminology and concepts as envisioned by the author combined with general introduction to northern work. This followed by a detailed summary of the Chick Lake study. The t h i r d section combines the information from the f i r s t two and presents some ideas about applying the concepts to the design of a northern hydrologic model. Since, of necessity, any major work i n the north w i l l require some f i e l d work there i s an appendix o u t l i n i n g the hard and expensive lessons that were learned during the study, as well as some guidelines on what to look for and some of the li m i t a t i o n s encountered while 'north of 60'. F i n a l l y , general conclusions and a summary round out the paper. -5-2 . 0 WHAT'S NORTH AND WHY The most s i g n i f i c a n t feature of the northern environ-ment i s the extreme winter cold. The low temperatures, the long hours of darkness, r e l a t i v e l y l i t t l e snow cover i n winter and the warm, dry, b r i e f summers of long s u n l i t days combine to produce an environment which i s foreign to our tra i n i n g , theories and understanding. Permanently frozen ground (permafrost) exists i n varying d i s t r i b u t i o n from the southern l i m i t of the continuous zone to the northern regions of the Canadian provinces. The scant available water and f l a t topography common to much of the heavily glaciated northern regions combined with the harsh environment are responsible for the development of the f l o r a l communities which play an important role i n c o n t r o l l i n g the hydrologic regime. Since t h i s study was an attempt to gain some insight applicable to culvert and erosion design, only the maintenance of natural drainage i s considered from these points of view. This eliminates t r u l y low ly i n g muskeg sinkholes, bogs and fens. The scenario which would generally apply i s that of a mildly sloping basin, with perhaps l o c a l i z e d f l a t s , that ultimately would require some form of treatment to control flow i f a structure (pipeline, road bed, etc.) were constructed i n the downstream reaches. To t h i s end an understanding of the mechanisms of basin response i s required i n order to model and f i n a l l y synthesize short term flood s t a t i s t i c s for return period events from meteorological records. Each important aspect of the environment i s considered separately, followed by a discussion i n general terms of the i n t e r r e l a t i o n between aspects of the environment and the mechanisms important i n northern regions. 2.1 PERMAFROST The most tangible evidence of the harsh environment l i e s below the ground surface as permanently frozen s o i l s and subsoils. An excellent summary of the terminology associated with the study of permafrost as well as a detailed map of the d i s t r i b u t i o n of the continuous and discontinuous perma-fr o s t zones has been prepared by Brown(1974). The aspects of t h i s phenomena of p a r t i c u l a r concern to hydrologists consist of: (a) the depth to the top of the frozen zone at a given time and location (the depth to the fr o s t table) (b) the material of the "active layer" (that surface strata that experiences annual freezing and thawing) (c) the areal extent of the permafrost. These three items interact with the rest of the environ-ment to change the basin c h a r a c t e r i s t i c s markedly over the summer season, while more subtle evolutionary changes occur over the years. With the onset of spring, what snow exists i s rapidly melted and either runs off or i s stored i n the surface voids - 7 -of the moss layer which overlies the concrete-like frozen peats (see Figure 2). This i n i t i a l rush of snowmelt generally causes few erosion problems i n small basins since the frozen surface material i s not easily, distrubed. As more solar energy i s absorbed, the f r o s t table moves down releasing material and water from the frozen grasp of winter. The rate of progress of the f r o s t table i s dependent on: (a) the amount of incoming energy to the surface (b) the transfer of.. t h i s energy to the frozen s o i l s . Local weather, climate, l a t i t u d e , aspect, topography and "high" vegetation cover (ie: tree cover) control the energy input while the surface and subsurface material, t h e i r history, l o c a l disturbance, type, colour., water content and r e l a t i v e location are important to the transfer of t h i s energy. It i s the l a t t e r area to which the bulk of the hy d r o l o g i s t 1 s special attention must be focused i n the development and use of a suitable technique for providing flood s t a t i s t i c s . After about the f i r s t two weeks of spring melt the fr o s t table has moved through the surface mosses into the s o l i d peat below. The rate of regression of the fr o s t front i s affected by the ins u l a t i n g value of the overlying material; as well as the incoming energy. I t i s i n the function of a thermal insulator that the c h a r a c t e r i s t i c s of unfrozen material become important. The common si t u a t i o n i n the d i s -continuous permafrost zone i s a ground cover of moss over peat, in which the vegetative mat provides excellent thermal protec-t i o n and the downward progress of the fros t front deccelerates as the summer progresses (see Figure 2). However, the - 8 -^SO&jT FfrX OJ. //J.JJO -9-in s u l a t i v e e f f i c i e n c y of the cover varies over two orders of magnitude depending on i t s moisture content ( G i l l , 1979), (Williams, 1968) being the poorest insulator when saturated. Thus the fr o s t table below minor l o c a l low spots may be two or three times deeper than an adjacent high perhaps only one metre away. This creates an impermeable surface below ground l e v e l more ir r e g u l a r than the surface topography and which may hold very s i g n i f i c a n t volumes of subsurface depression storage. An extension of t h i s idea i s the concept that i f the topography of the f r o s t table changes throughout the season, some basic basin c h a r a c t e r i s t i c s such as basin area, the flow pattern and depression storage which are often considered "fixed" can i n fact vary s i g n i f i c a n t l y throught the season and can be r a d i c a l l y changed by new construction. A surface disturbance such as a road, seismic or survey c u t l i n e or game t r a i l with increased in s o l a t i o n due to tree removal and possibly impaired i n s u l a t i n g c a p a b i l i t y through disturbing, or compressing the cover can cause a depression i n the sub-surface impermeable layer and hence a major change i n hydrologic response. Upland flow c o l l e c t s i n the depression further disrupting the ins u l a t i n g c a p a b i l i t i e s . What can f i n a l l y happen i s a " s h o r t - c i r c u i t i n g " of the upland area to an adjacent basin, thus changing the areal c h a r a c t e r i s t i c s of each basin. An estimate of the position of the f r o s t table at a given location and time i s possible by f i t t i n g an exponential decay curve to a few observed depths of thaw taken throughout a summer season. F a i l i n g observations an assumption of 15 cm of thaw approximately two weeks af t e r the passage of the 0° C i s -10-isotherm provides an i n i t i a l point which appears reasonable i n comparison to observed data. A shallow d r i l l hole using a hand auger w i l l disclose the average maximum depth of thaw since color variations c h a r a c t e r i s t i c of weathering w i l l appear only i n the material of the active layer. I t i s suggested that several such probes be made i n a variety of locations to provide an average value as well, as confirm the homogeneity of the surface materials and thickness. 2.2. VEGETATION AND SOILS The importance of the material cover, to permafrost hydrology results from i t s e f f e c t on the rate of the basin f r o s t table lowering through the summer season which i n turn affects the basin c h a r a c t e r i s t i c s . These ef f e c t s are propor-t i o n a l to changes with depth of the material properties them-selves, either within the same horizon or at the interface between horizons. The magnitude of the variations dictate whether the subsurface flow and storage c h a r a c t e r i s t i c s can be characterized by a single, non-variable parameter, or by para-meters which must be allowed to change with time. For example, a northern basin of exposed bedrock or thin organic layer over-ly i n g a s i l t y , clay t i l l of low porosity and permeability could reasonably be described by a single parameter si m i l a r to that used i n the south. A l t e r n a t i v e l y , i n an area with a deep organic s o i l with a thick active layer, formulations for storage, hydraulic conductivity, time of concentration a l l varying as a function of date, antecedent conditions and event -11-ntagnitude may be required. It i s t h i s l a t t e r s i t u a t i o n which i s common along northern transportation corridors and i n areas where development i s l i k e l y to take place, and i s the case under consideration. Starting above the surface, the open black spruce forest and shrubs reduce the size and v e l o c i t y of incoming raindrops, thus reducing t h e i r erosion p o t e n t i a l . The sphagnum moss cover has a s u f f i c i e n t l y high i n f i l t r a t i o n rate that overland flow i s v i r t u a l l y eliminated except when the water table i s p a r t i c u l a r l y high, as may be the case i n early summer when the f r o s t table i s near the surface. Progressing downward the moss grades into peat, the hydraulic conductivity and porosity of which decrease with depth. Below t h i s organic mat l i e s the mineral s o i l , generally a permanently frozen.remnant of g l a c i a l times. While i t can be generally assumed for estimating peak flows that t h i s frozen subsoil of fine grained material i s impermeable, t h i s i s not s t r i c t l y true and d e f i n i t e movement of l i q u i d water i s possible i n the frozen zone (Carlson, 1979). Result i s an examination of the s o i l p r o f i l e encountered at the Chick Lake study area together with s o i l properties are shown i n Figure 3. While i t i s not clear, from the data, a r e l a t i o n between time of concentration of the basin and the hydraulic conductivity i n the zone of water movement should e x i s t . DEPTH (MM) son COLUMN 1////FIED SOIL DESCRIPTION yyDRAULtC CONDUCTIVITY (/0-'c~/s*c) o . /oo 200 300. 400 500 600 7O0 T T 5 T 3 T P+ Y MS pre** BJ f i s r & . t . e ^ ^ ^ a n f i i ^ . ^ J. 48 «*» />?*>, rive CesiJeiff /rt<T/-eas*s I +*i*,t a -c / (V* ^ff<P' rfy J".// , f*Y, low jeAsAc tn.e+1 t*d} feai"*<».//jr *«"«^ __ ' Pes-ma.- fi-ost'- f>-er*tajtoxfty I o CURVE BASED OA/ POO/? ESTIMATES //S MOT RELIABLE, BUT DOES WD/CATE THE TfZEND F/GURE 3 : TYP/CAL CU/CKUME^SO/L PROFILE DATA PORO s/ry (/j) DEPTH (%) M M ) 500 600 700 t DATA. O U T L I E R S S U S P E C T B E C A U S E O F D I F F I C U L T I E S HANDLIM6 L O O S E ORGAHMICS - E S T I M A T E D R E A L P O R O S I T Y : n 87-rx/o-3) D +0.335 - POROSITY USED TO ESTIMATE POTENTIAL STORAGE. <n--(-3.S75*IO-3)D-r0.23 ( O s D E P T H ) -13-2.3 POTENTIAL AND AVAILABLE STORAGE Potential storage i s considered to be that storage volume p o t e n t i a l l y available in, the surface horizon assuming no water i s being stored either as a re s u l t of previous ra i n , snowmelt or ground melt, and includes the "subsurface" depressional storage caused by low areas i n the frozen i n t e r -face. Based on the active layer thaw curve and s o i l porosity, a relationship of potential storage versus time can be derived (Figure 4) . Available storage i s that portion of the poten t i a l storage not already occupied by l i q u i d water, at a given time. Thus, potential storage at a given time during the summer i s predictable (within p r a c t i c a l limits) given the r e l a t i v e consistency of the active layer melt and the s o i l properties. The available storage i s a function of potential storage and antecedent conditions which, because of the areal v a r i a b i l i t y associated with p r e c i p i t a t i o n , can be considered at least p a r t i c a l l y random i n nature. 90 I 80 1 • >* J*J 70 0. k 30 0 to / DERIVED BY NUMERICALLY COMB/NWG TU£ MEA/V OEPTP / CURVE /1/VD POROS/Ty DATA OF SURE4CE MATER/A LS POTE/VT/AL STORAGE = J (Pofios/ry)- <£ (£>£RTH) n i I • i i I 0 20 MAY /S~ AT CWCK (.& 40 60 SO /OO /20 f40 DAYS /A/TO THE SUMMEP MELT SEASON /60 F/GU/9E 4: POT^A/T/AL STOr?AG£ -15-2.4 THE EFFECTS OF PERMAFROST MELT ON RATE OF RUNOFF AND POTENTIAL STORAGE Ignoring antecedent moisture for the present, consider the increase i n potential storage due to the increase i n thaw depth as summer progresses. I n i t i a l l y the entire active layer i s frozen and snow covered. Snow.melt occurs and runs o f f f a i r l y rapidly contributing to the spectacular spring break-up c h a r a c t e r i s t i c of the large northern r i v e r s . As the depth of thaw increases, potential storage i n the moss layer i s opened and two things may happen. If the active layer i s r e l a t i v e l y dry, an impermeable layer of ice w i l l progress downward with the thawing front and the thawed potential storage w i l l be converted almost t o t a l l y to. available storage. Ale r n a t i v e l y , i f the active layer i s saturated, the potential storage i s available only at the rate the moisture freed by thawing can be removed through some combination of evapotranspiration and drainage. Therefore, the available storage i s a function of the depth to the f r o s t table and moisture present at a given time. -16-2 . 5 EVAPORATION The removal of water from storage occurs i n two ways, drainage and evaporation. Due to the large storage c a p a b i l i t i e s of the surface layer once thawed, and the r e l a t i v e l y slow move-ment of water through the s o i l mantle, evaporation i s an important factor i n determining the available storage at the occurrence of a major p r e c i p i t a t i o n event as well as when considering the seasonal water balance. Using the Thornthwaite (Thornthwaite and Mather, 19 49) approach based on mean monthly data, a seasonal pot e n t i a l evaporation of 32 6 mm i s calculated. This compares favorably with 180 mm shown i n the Hydrologic Atlas of Canada (A.E.S., 1977) and a few actual measurements at Norman Wells (A.E.S., 1972-77) showed 340 mm. The re s u l t s are shown as Figure 5 and Table I for the Chick Lake study. Hare and Thomas (1970) i l l u s t r a t e d the average p o t e n t i a l losses at Chick Lake to be i n the order of 240 mm. S p e c i f i c phenomena contributing to these losses include the constant l i g h t winds, long days with r e l a t i v e l y high a i r temperatures (see Table I ) , the generally moist moss cover and low r e l a t i v e humidity. Dingman (1971) commented i n reference to a similar study i n Alaska that the evaporative losses are expected to be low, owing to the non-vascular nature of the moss cover and the low demands of the r e l a t i v e l y open tree and shrub vegetation. While t h i s may be true i n absolute terms, evidence i s that the mosses "wick" moisture upward and provide large surface areas conducive to evaporation. Bredthouer (19 79), TABLE I: Calculation of Evaporation at Norman Wells, N.W.T., by Thornthwaite's method based on mean monthly data. JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC YEAR Temperature (°F) -19.7 -15.8 -2. 18.7 41.2 56.6 60.9 55.7 42.5 24.7 -.6 -14.6 Temperature ( C) -28.7 -26.6 -18. T 9 -7.4 5.1 13.7 16.1 13.2 5.8 -4.1 • -18.1 -25.9 1 _ 1.03 4.60 5.87 4.35 1.25 — — — 17.1 Unadjusted Potential Evap (mm) - - - - 37. 60. 80. 60. 42. - - -Adj. factor of l a t . + 50° .74 .78 1. 02 1.15 1.33 1.36 1.37 1.25 1.06 .92 .76 .70 Adjusted Potential Evap. (mm) - - - - 49.2 81.6 109.6 75. 44.5 - - -P r e c i p i t a t i o n (in) .82 .68 49 .56 .60 1.44 2.21 2.43. 1.33 .99 .86 .76 13.17 P r e c i p i t a t i o n (mm) 20.8 17.3 12.4 7.0 15. 2 36.6 56.1 61.7 33.8 25.1 21.8 19.3 348. Precip-Potential Evap (mm) 21.. 17. 12. 7.0 -34. -45. -53.5 -14.3 -10.7 25. 22. 19. -58.5 Accumulated Potential Water loss (mm) - - - (0) -34. -79. -132.5 -146.8 -157.5 - - -Storage ST (mm) 263. 280. 292. 299. 268. 230. 192. 183. 176. 201. 223. 244. Change i n storage dST (mm) +21 +17 +12. +7. -31. -38. -38. -9. -7. +25. 22. 19. AE Actual Evaporation (mm) - - -. - 46. 74. 94. 71. 41. - - - 326 D e f i c e i t (mm) - - - - 3. 7. 26. 5. 4. - -Surplus (mm) _ _ _ - 0 0 0 0 0 - - -I h-1 I 1 8 " F/GURE 5 :£MPORAT/ON AT A/ORMA/V WELLS W.T CALCULATION BY TA/OATHH#/T£'S METHOD 6/S£D OA/ 30 Y/S CL/A7AT/C A4EAA/S -19-also of C.R.R.E.L., reports that lysimeters f i l l e d with sphagnum moss show s i g n i f i c a n t l y higher water loss rates when compared to adjacent Class A pans i n a study near Fairbanks, Alaska. While the seasonal evaporation rates are not large when compared to those experienced in. southern regions, comparison to summer and annual p r e c i p i t a t i o n shows that evaporation alone could p o t e n t i a l l y account for a l l of the available moisture. Furthermore, with the wicking action of the moss, the loss rate i s much less r e s t r i c t e d when the water table f a l l s below the surface than the usual southern case of dealing with mineral or decomposed organic s o i l s . In r e l a t i v e terms, with a t o t a l annual mean p r e c i p i t a t i o n of 330 mm (Burns, 1973) of which 170 mm occurs as snow and runs o f f before evaporation rates.reach a maximum, the poten t i a l exists for a l l of the summer rains to be consumed by evaporation. The usual low levels of small lakes and ponds i n July and August would argue i n favour of high evaporative losses. The main point i s that evaporation i s important as a primary "drainage" mechanism removing water from the mantle and increasing the available storage. This storage volume controls the magnitude of the flood peak and the shape of the hydrograph. Furthermore, evaporation generally accounts for more than 50% of the summer p r e c i p i t a t i o n as shown by observa-tions at Chick Lake (Figure 10) and thus must be considered i n water balance calc u l a t i o n s . -20-2.6 SURFACE DISTURBANCE As previously mentioned, basin area can change as a r e s u l t of the subsurface " s h o r t - c i r c u i t i n g " caused by a trough or ridge developing i n the f r o s t . t a b l e . This distrubance could take the form of the construction of a seismic l i n e or game t r a i l which tend to form a trough due to increased energy reaching the surface and the compression of the peat mat, thus reducing i t s insulating value. A ridge might be caused by the construction of a road where a r t i f i c i a l i n s u l a t i o n or a thick layer of well draining gravel i s introduced, providing extra protection to the frozen s o i l s , and allowing the perma-fr o s t l e v e l to, or a p i p e l i n e , which i n i t s e l f provides an obstacle, but when c h i l l e d gas i s the product being moved a f r o s t bulb develops around the l i n e and i s maintained frozen throughout the year. This l a t t e r s i t u a t i o n was examined by Soulis and Reid (1976) i n a separate study at the Chick Lake s i t e . Other natural disturbances which could change the flood c h a r a c t e r i s t i c s of an area include the p r o l i f e r a t i o n i n recent years of the Canadian beaver and forest f i r e s which are general-l y allowed to burn unchecked i n the muskeg t e r r a i n . -21-3. THE CHICK LAKE STUDY 3.1 BACKGROUND The Chick Lake Study was intended to provide an under-standing of the hydrology of the Northern Boreal Forest under-l a i n by permafrost. This landform constitutes a major portion of the Mackenzie Valley, the area most developed i n the North-west T e r r i t o r i e s and most l i k e l y . t o sustain further development primarily by the mineral, petroleum and transportation indust-r i e s . In terms of the proposed pipeline development, erosion control and small basin drainage works were estimated to represent 10% (or one b i l l i o n dollars) of the c a p i t a l outlay. Of the approximate one t h i r d of the route i n the discontinuous zone, about 70% lay i n the r e l a t i v e l y f l a t open black spruce forest characterized by poorly defined drainages and abundant shrub and moss cover. Considering that s i g n i f i c a n t savings could be r e a l i z e d i f a less conservative design could be j u s t i f i e d , a hydrological research program i n the Chick Lake study area was set up i n conjunction with several other studies. 3.2 THE STUDY AREA The Chick Lake s i t e provided a single s i t e where a number of separate studies could be pursued and i n t e r r e l a t e d . The s i t e i s 80 km northwest of Norman Walls, Northwest T e r r i t o r i e s and access i s limited to charter a i r services or an arduous overland journey. During spring and f a l l the area i s v i r t u a l l y inaccessible except by helicopter and t h i s lack -22-of public access was a major advantage of the area as an integrated research s i t e since the environmental studies required control i n order to establish baseline data, impossible to acquire i n an area accessible to the public. To t h i s end four seasons of f i e l d data on vegetation and small mammals (Douglas, 19 77) was obtained as well as some subsurface flow studies (Soulis and Reid, 1977). The lake provided an assured water supply, as well as allowing the use of larger f l o a t or s k i equipped a i r c r a f t to ferry equipment and personnel. F i n a l l y , a major archaeological s i t e exists at the lake outlet to the Donnally River which required the establishment of a camp for study at some point i n time. From an engineering viewpoint the gently sloping, deep organic s o i l s on the west side of the lake were t y p i c a l of much of the proposed pipeline route. This route passed near the lake, thus before and afte r studies were possible i n the realms of fauna, f l o r a and hydrology, both upslope and down-slope from the disturbed r i g h t of way. F i n a l l y , the lake i t s e l f provided easy l o c a l transport by power boat which p o t e n t i a l l y allowed frequent and regular service to the scien-t i f i c s i t e s , as well as some amenities for personnel on s i t e for extended periods. 3.3 LOCAL TOPOGRAPHY, CLIMATE, GEOLOGY AND VEGETATION The study area i s located i n a lake basin i n the central Mackenzie River Valley approximately 80 km northwest of Norman Wells, at approximately 65°52' N and 128°07' W (see Figure 1). The lake basin i s surrounded by the rugged t e r r a i n of the -23-Franklin Mountains where elevations range from 135 m ASL at lake l e v e l to 825 m ASL on top of Gibson Ridge, the most prominent l o c a l feature and the northern spur of the Norman Range which forms the western flank of the Franklin Mountains. The t e r r a i n , while extremely rugged, has been subdued by passage of the continental ice sheets, the l a s t during the Pleistocene era which moved i n a northwesterly trend leaving a p a r t i c u l a r l y l i n e a r landscape of p a r a l l e l ridges and grooves. This i s especially evident when viewed from the a i r between Norman Wells and the study area... The underlying bedrock i s faulted Cretaceous shale and folded and faulted Devonian limestone which contains some o i l and gas deposits. Over-ly i n g the bedrock i n the v a l l e y , i s a dense s i l t y t i l l generally covered by a layer of lacustrine clays and s i l t s deposited when the area was covered by g l a c i a l meltwater. The surface stratum i n the study area consists of i c e -r i c h layers -of poorly sorted s i l t y clay and s i l t y sand over-l a i n by thick (up to 2 m) organic surface layers. The actual surface i s characterized as weakly to moderately hummocky (hummock diameter 0.50 to 1.0 m, height 0.25 to 0.40 m). Permafrost i s found throughout the entire area, with an average maximum depth of thaw (as surveyed i n 1975 and 1976) of 0.44 m. Spot measurements from a l l years when the s i t e was v i s i t e d indicate the mean progress of the seasonal thaw i s consistent from year to year, as i s the maximum thawed depth. At any time, up to 50% v a r i a t i o n from the mean thaw depth i s observed, often between two points within one meter of each other, dependent on -24-whether the location i s on a hummock (least thaw) or i n a trough. This type of v a r i a t i o n i n the f r o s t table i s an exaggerated r e f l e c t i o n of the surface topography on a micro-scale and the major source of changing subsurface depression storage. Vegetation i n the study area consisted of an open black spruce forest, average tree height approximately 4 to 5 meters, but highly variable. The largest specimens are found on the lakeshore, reach heights of 10 m and apparently enjoy some moderation of climate. Abundant shrubs and lichens provide ground cover dominated by blueberries, Labrador tea and lichens. These are rooted into a mat of sphagnum moss over peat i n which the "active" layer of seasonal thaw i s generally confined. It i s t h i s layer of moss and peat which i s respons-i b l e for the hydrologic response of the basin. Climate experienced i n Chick Lake, as extracted from h i s t o r i c a l records (Burns, 1973) at Norman Wells (80 km S.E.) and Fort Good Hope (60 km N), i s c l a s s i f i e d as "Dry Continental". The summer i s short and cool followed by long cold winters. P r e c i p i t a t i o n i s low, averaging approximately 330 mm annually, approximately two-thirds of which f a l l s as snow. The mean annual temperature of -6°C places the area i n the northern fringes of the discontinuous permafrost zone (see Brown, 1974). Climate c h a r a c t e r i s t i c s have been summarized i n Table I I . TABLE II: Mean Monthly Weather Characteristics, Norman Wells & Fort Good Hope, N.W.T. (Burns, 1973) JAN . FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC YEAR )rman Wells mean d a i l y temp ( C) -28.7 -26.6 -18.9 -7.4 5.1 13. 7 16.1 13.2 5.8 -4.1 -18. 1 -25.9 -6.3 mean d a i l y max. temp ( C) -24.6 -22.0 -1267 -1.1 10. 9 19.5 21.8 18.5 10.1 - .8 -14. 7 -22 -1.4 mean d a i l y min temp ( C) -32.8 -31.1 -25. -•13. 7 - .6 7.8 10.2 7.8 1.6 -7.4 -21. 7 -25. 8 -11.2 no. days with f r o s t 31 28 31 29 17 1 — 1 11 29 30 31 239 mean ra i n (mm) .3 1.3 8.9 35.8 56.1 61.7 28.2 2.8 3 - 195.3 mean snow (mm) 213. 185 127 135. 64. 7.6 - - 58. 231 218 193 1433 mean p r e c i p i t a t i o n (mm) 20.8 17.3 12.4 14.2 15.2 36.6 56.1 61.7 33.8 25.1 21. 8 19.3 334.5 no. days measurable ra i n - - 4 9 11 12 9 2 - - 47 no. days measurable snow 13 12 10 8 4 - - - 3 11 14 12 87 TABLE II: Mean Monthly Weather Characteristics, Norman Wells & Fort Good Hope, N.W.T. (continued) (Burns, 1973) JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC YEAR Fort Good Hope mean d a i l y temp ( C) -30.8 -28.9 -22.3 -10. 6 3.5 12.8 15.4 12.1 4.6 -5.9 -20. 9 -28. 6 -8.3 mean d a i l y max temp ( C) -26.1 -23.9 -15&7 -3. 4 9.8 19. 8 22. 18.5 9.6 -2.1 -16. 6 -24. 3 -2.7 mean d a i l y min temp ( C) -35.4 -34.1 -28.9 0 -2.8 6.2 8.7 5.7 -.5 -9.8 -25. 2 -32. 9 -13.9 no. days with f r o s t 31 28 31 30 22 2 — 4 17 30 30 31 256 mean ra i n (mm) - - - 1. 8 8.1 35.3 45. 7 51.3 28.4 3.8 # 5 175. mean snow (mm) 160. 162. 157. 122. 79. - - - 43. 231. 259. 157. 1371. mean p r e c i p i t a t i o n (mm) 16. 16.2 15.7 13. 7 15.7 35.3 45.7 51.3 32. 7 26.9 26. 2 15. 7 311.4 no. days measurable ra i n - - - - 4 9 10 13 9 2 - - 47 no. days measurable snow 9 9 9 6 3 - - - 2 9 11 10 6 8 I l -27-3.4 DATA COLLECTION HISTORY I n i t i a l work began i n 1973 when b i o l o g i c a l studies were i n i t i a t e d at the s i t e , however i t was not u n t i l l ate i n the summer of 19 74 that studies of the hydrology, including water movement i n the subsoil, were i n i t i a t e d . During the summers of 1974, '75 and '76 some data was co l l e c t e d i n i t i a l l y using Stevens F recorders which required service on a weekly basis, and l a t e r an attempt was made with Ott bubbler recorders. The f i r s t year, 19 74, was a year for learning, as the o r i g i n a l containment dikes f a i l e d by piping and as a r e s u l t no useful record was obtained. This was rather unfortunate as i t was a very wet year. However, the requirement to l i n e the s t i l l i n g basin to reduce thaw and piping by increasing the length of the drainage path was established. Unfortunately, 1975 was an exceptionally dry year and while the stream gaging equipment functioned, very l i t t l e flow record was produced. In 19 76 the Ott bubbler-type recorders were t r i e d but a rather unique problem developed. The l o c a l mouse population found the r i g i d black polyethylene p l a s t i c tubes (used to lead to the bubbler head) a gastronomical delight and damaged the tubes, rendering the instruments useless. This was the f i r s t year when the s i t e s were v i s i t e d infrequently and thus t h i s "foolproof" recorder f a i l e d to l i v e up to expectations. Of interes t while discussing the Ott recorders, another d i f f i c u l t y with them was the complex and unreliable pen mechanism which caused some problems, although i t did not af f e c t the study. Further, d i f f i c u l t y i n handling of the compressed nitrogen gas bottles both at the undeveloped s i t e s and i n transport precluded further use of these gages. - 2 8 -The period of useful records was the summer of 1977 when four Stevens A recorders with 90 day mechanically driven s t r i p charts were used. These were i n s t a l l e d i n f u l l y l i n e d s t i l l i n g basins, with eight inch diameter f l o a t s , and the counter-weights enclosed i n a s t i l l i n g well. At a l l four s i t e s these units functioned well, as did the tipping bucket r a i n gage which used a "Weather-Measure" s t r i p recorder. Generally, the r a i n gage set-up, while " r u s t i c " was standard (see Figure 6) while the V-notch weirs and basins were at least somewhat novel (see Figure 7). • GUYED SUPPORT FOR ALTER W/NO SHIELD T/PPIA/G BUCKET RAM GAGE HEAVILY REINFORCED 2"4 AVSTROMEAtT PLATFORM FIGURE 6 : CUT-AWAY OF RAIN GAGE SET-UP - 3 0 -J ^ Co 38 JL > y> I CO -31-3.5 GAGE SITES After the snowmelt and break-up of the lake had occured, (allowing economical access by. f l o a t plane) the s t i l l i n g basins were set up. The i n s t a l l a t i o n , , based on suggestions by Rahn (Rahn, 1967), entailed reconstructing the containment dikes, laying the p l a s t i c basin l i n e r on the c a r e f u l l y cleared and cleaned basin (to avoid l i n e r damage), i n i t i a l l y allowing the water to flow underneath i t , i n s t a l l i n g the st e e l "knife-edge" V-notch to the plywood cutoff, sandwiching the p l a s t i c membrane between the st e e l and plywood (see Figure 7), and i n s t a l l i n g the s t i l l i n g well. Since there i s no e f f e c t i v e glue or tape sealing method for polyethylene sheet (except perhaps using a heat gun which i s impractical under f i e l d conditions) and the objective was to have no holes at which piping might be induced through the membrane, the method of s o l i d l y i n s t a l l i n g the s t i l l i n g wells required some innovation. Previously iron bars had been d r i l l e d several feet into the permafrost and these provided a s o l i d instrument foundation. By "capping" these near ground l e v e l with a plywood disc a suitable platform was begun. Over the plywood was placed the p l a s t i c sheet, and the s t i l l i n g well was placed on top. The s t i l l i n g wells consisted of two 10 gallon gasoline kegs, one with both top and bottom removed, the other with only the top removed. The l a t t e r , with 2 small flow holes d r i l l e d i n the side, was placed bottom down on the plywood, i t s small rim locking on the appropriately cut dis c . A few heavy rocks were placed inside for s t a b i l i t y . Next the other keg was fastened on and on top of t h i s was bolted a plywood table on -32-which the recorder was mounted. Once together, the unit was s o l i d , and after being heavily guyed with wire rope i t was very stable. At t h i s point i n time the upstream edge of the l i n e r i s sunk into an upstream cutoff.trench and the flow i s directed over, rather than under the p l a s t i c sheet. Two points are worthy of note. One i s the need for an organized and f a i r l y rapid pace between closing the "under p l a s t i c channel" and setting the upstream cutoff. In t h i s period the s t e e l V-notch must be i n s t a l l e d and the membrane sandwiched under i t as well as placing, i f not guying the s t i l l i n g w ell. Care must be exercised not to damage the p l a s t i c or allow the water pressure to tear the sheet. Secondly, i t . i s important to lay only a single layer of polyethylene. A i r trapped between two sheets causes no end of problems including f l o a t i n g the l i n e r up out of the cutoff or dragging part of the membrane into the V-notch. The water trapped below the p l a s t i c i s gradually forced sideways as the basin f i l l s and causes no problems. F i n a l l y , the instrument i s guyed and l e v e l l e d , and as the basin f i l l s the zero flow point i s registered. A manual gage and a bridge to the s t i l l i n g well are convenient. At Chick Lake i n 19 77 these a c t i v i t i e s constituted about 3 man-days per s i t e , a l l of the work done without power tools of any kind, and the major clearing done previously. Approximately two f u l l days should be allowed for the i n i t i a l c learing, dike prep-aration and setting of the iron bars to provide the non-settling foundation for the instrument. F i n a l clean-up i n the f a l l required one and a half man-days per s i t e . - 3 3 -The r a i n gage was placed in the clearing created by the inter s e c t i o n of the C.N.T. rig h t of way and that of an abandon-ed winter road (see Figure 8),. ..This provided more than adequate clearance from l o c a l vegetation and other i n t e r -ference to the air-flow patterns. The gage consisted of a standard bucket (approximately .10 inches i n diameter) equipped with a tipping bucket mechanism that provided an e l e c t r i c a l " c l i c k " for each 0.01 inches of r a i n . The rim was the standard four feet above the l o c a l ground surface and wind ef f e c t s were reduced by an A l t e r s h i e l d placed i n the s p e c i f i e d manner. Response from the tipping bucket was recorded by a mechanically driven s t r i p chart, with a maximum record length of 60 days. The recording instrument which.was enclosed i n an insulated weatherproof box, performed well. The entire set-up was heavily b u i l t and guyed i n order to reduce possible i l l e f f e c t s from the somewhat destructive i n t e r e s t of the l o c a l fauna. Bear and moose can be p a r t i c u l a r l y destructive, however, again the mice cause the majority of the problems and have been known to gnaw e l e c t r i c a l leads causing shorts or creating situations where batteries drain and render e l e c t r i c a l l y driven instruments useless. The alternative was to construct a semi-permanent structure; an expensive and d i f f i c u l t task considering the a i r f r e i g h t and handling involved getting materials to the s i t e . With respect to the smaller members of the animal community, care must be exercised not to create nesting s i t e s i n an instrument set-up, p a r t i c u l a r l y near any free moving parts. -35-3.6 CHICK LAKE STUDY BASINS Three small creeks; draining into the south shore of Chick Lake were chosen as t y p i c a l of the s i t u a t i o n under study as well as maintaining the option of 'before and a f t e r ' monitor-ing i f the pipeline were b u i l t . Three gage s i t e s were located near the lakeshore and a fourth gage was located on the upstream end of one of the creeks. This provided gages upslope and downslope of the proposed pipeline location (see Figure 8). Basin c h a r a c t e r i s t i c s are summarized i n Table II while subsoil conditions were presented e a r l i e r i n the discussion on s o i l s and in Figure 3. The important information i s conveyed i n the mean poten t i a l storage derived by combining the subsoil porosity information and the depth to the f r o s t table curve, as shown in Figure 4. Delineation of the i n d i v i d u a l drainage basins was attempt-ed using a small scale contour map based on a e r i a l photographs. While the contour i n t e r v a l was small, analysis of the flow data indicates the basin divides may have been i n c o r r e c t l y placed. A problem exists i n dealing with such basins with poorly defined divides and dominant subsurface flow i n that the surface may not r e f l e c t what i s going on below. This i s es p e c i a l l y true i n a permafrost s i t u a t i o n since variable lower-ing of the f r o s t table can d r a s t i c a l l y a l t e r the basin shape. It would appear that part of the area attributed to basin 1 i s contributing to the ungaged stream to the east. -36-3.7 CHICK LAKE - DATA PRESENTATION AND ANALYSIS Stream gages were i n s t a l l e d i n early June, 19 77 and removed i n early September with no apparent malfunctions. The rain gage functioned properly during the same period. Total measured p r e c i p i t a t i o n in 19 77 was 105 mm which compares favorably with 67 mm recorded in 1975, a p a r t i c u l a r l y dry summer and 158 mm i n 1976, a very wet summer. Histogram of 1977 p r e c i p i t a t i o n i s presented i n Figure 9. Total summer pr e c i p i t a t i o n for the same periods (June through August) i n 1975, '76 and '77 for Norman Wells and Fort Good Hope were 83 mm, 86 mm and 67 mm and 58 mm, 77 mm and 114 mm respectively. While d a i l y temperatures were not recorded for s u f f i c i e n t periods to present useful, plots, diurnal range and the trend of the d a i l y mean follows that observed at Norman Wells, allowing for l o c a l variations i n weather caused by the compact convect-ive systems which dominate the summer weather and the proximity of Norman Wells to the Mackenzie River. Streamflows as recorded i n 19 7 7 are also presented i n Figure 9, along with the "best f i t " obtained using the Clarke's method computer model. Table II provides a summary of the data c o l l e c t e d and the results of the analysis. A problem i n defining the basin areas and boundaries i s evident by examining the V/A (total recorded flow volume over basin area) r a t i o and by p l o t t i n g the f a l l i n g limb of the hydrographs on log paper. However, prec i s e l y how to "improve" the estimates i s not clear considering the area c h a r a c t e r i s t i c s i s variable with time and the 1977 data did not provide s u f f i c i e n t l y separate events, -37-JUNE JULV JUNE JULY riGURE 3 : /97Z MJNRLL f RUNOFF DATA, CHICK LAKE o - 3 8 -o r a l o n g e n o u g h r e c o r d t o i n d i c a t e t h e t r e n d . C o m p a r i s o n o f b a s i n r e s p o n s e t o p a r t i c u l a r p r e c i p i t a t i o n e v e n t s g i v e s some i n s i g h t i n t o t h e c h a n g e s i n t h e b a s i n w i t h t i m e . W h i l e t h e i n t e n s e e v e n t o f A u g u s t 1 s o l i c i t e d no r e s p o n s e o n a n y s t r e a m c h a r t , e v e n m i n o r e v e n t s i n m i d J u n e w e r e r e c o r d e d o n t h e h y d r o g r a p h . T h i s p r o v i d e s s u p p o r t f o r t h e c o n t e n t i o n t h a t r e s p o n s e o f a p e r m a f r o s t b a s i n i s d o m i n a t e d b y t h e d e p t h t o t h e f r o s t t a b l e ( i e : t h e d a t e i n t o t h e summer s e a s o n ) a n d a n t e c e d e n t c o n d i t i o n s . W h i l e no d a t a was c o l l e c t e d o n e v a p o r a t i o n , i n d i c a t i o n s f r o m w o r k d o n e i n A l a s k a a r e t h a t i t i s e x t r e m e l y i m p o r t a n t i n t e r m s o f a c c o u n t i n g i n w a t e r . b a l a n c e c a l c u l a t i o n s a n d as a d r a i n a g e m e c h a n i s m i n c r e a s i n g t h e a v a i l a b l e s t o r a g e . -39-4.0 DATA PREPARATION AND ANALYSIS The basis of the analysis was the simple single event, fixed parameter Clark's hydrograph model programmed for use with an i n t e r a c t i v e graphics terminal. The methodology of the model i s described by Gray (Gray, 197.0.)., the o r i g i n a l work presented by Clark (Clark, 1945) and used,by the United States Corps of Engineers i n t h e i r HEC-1 Flood Hydrograph Package (HEC, 1973). The s t r i p charts obtained .from the four recorders for the summer of 1977 were f i r s t d i g i t i z e d by Water Survey of Canada and then converted into hourly flow records using a program written by the author. This was converted into a season-a l hydrograph plot and was input i n t h i s form to the Clark model. The p r e c i p i t a t i o n record was manually reduced into a histogram suitable for input to the model together with flow data and was used to estimate the basin parameters of time of concentration and a storage constant. An estimate of the t r a v e l time versus contributing area was made for each catchment based on watershed shape and the assumption that flow v e l o c i t y would be r e l a t i v e l y constant throughout the basin at any given time. This i s reasonable since the basins have f a i r l y constant slopes and the surface layer i s consistant throughout. The baseflow component was assumed to be zero i n a l l cases. Input data i s i l l u s t r a t e d i n Figure 9. The data for each s i t e was examined using the two step i t e r a t i v e procedure programmed for the graphics terminal. The f i r s t step involves estimating e f f e c t i v e p r e c i p i t a t i o n by using the two f i t t i n g parameters of i n i t i a l loss and i n f i l t r a --40-ti o n rate to match flow estimated by the model to that recorded. The i n i t i a l loss could be considered that p r e c i p i -tation which i s i n i t i a l l y required to "wet" vegetation and s o i l surface before flow begins, and i s l o s t forever to evaporation. I n f i l t r a t i o n would be the minor losses to the frozen sub-soil which are not e n t i r e l y impermeable, losses around the weir, and evaporation since the model makes no provision for these losses which would be s i g n i f i c a n t over the four week period of analysis. Figure 1 0 i l l u s t r a t e s the relationships obtained between i n f i l t r a t i o n rate and i n i t i a l l o ss. The values chosen to go into the second step of the hydrograph synthesis turned out not to be c r i t i c a l but were chosen to r e f l e c t the "expected" losses, approximately half of the t o t a l losses to each of i n i t i a l loss and i n f i l t r a t i o n . The model i s extremely sensitive to the choice of storage constant and time of concentration except when large times of concentration were required, thus within a few i t e r a t i o n s quite an acceptable and unique f i t with the recorded hydrograph was obtained. Figure 9 i l l u s t r a t e s the "best" f i t condition for each hydrograph and Table III summarizes input data and r e s u l t s . The above results do not show any of the patterns one would expect of four basins close together i n similar t e r r a i n and of such si m i l a r c h a r a c t e r i s t i c s of slope, aspect, and basin shape. The obvious conclusion i s that some of the data i s probably incorrect; and the most l i k e l y problems are with basin area and subsurface flow bypassing the weirs. It was extremely d i f f i c u l t to delineate the apparent basin boundary TABLE I I I : SUMMARY OF RESULTS Basin No. 1 2 Area (hectares) 22. 4 15. 3 46 61. 8 Basin Length (m) 1450 1000 1575 1350 Mean Basin Slope (%) 3. 7 3. 7 3. 4 3. 9 Stream length (m) 600 150 400 350 Stream slope (%) 3. 3 2. 5 3. 5 4. 4 Peak flow (L/S) 12 5 26 25 Peak flow (L/sec/ha) • 54 • 33 • 57 • 40 Average Basin Runoff Depth (mm) 33 7. 52 31 Time of Concentration, T c (hours) • 80 10 40 80 Storage Constant, R (hours) 120. 40 100 80 I ro l -43-from the available mapping, and the moss covered t e r r a i n introduced further uncertainty with respect to the location of the r e a l divides. Basin 2 appears to have been overestimated while basin 3 has been underestimated. The r a i n f a l l losses (the difference between the ra i n which f e l l and that which eventually showed up as runoff) were i n the order of 70 mm and t h i s volume never did appear as subsequent streamflow. This volume i s approximately equal to the amount of evaporation one would expect during the period analysed. As has been previously discussed, annual evaporation i s i n the order of 24 0 mm. The s i g n i f i c a n t feature of the results is. the r e l a t i v e l y large values obtained for time of concentration and storage constant considering the size and slope of the basins. 'Ignoring s i t e 2, times of concentration of 2 to 4 days for basins less than 75 hectares in area implies that the super-position of events i s important i n defining the sequence of storms respons-i b l e for major runoff. It c e r t a i n l y negates e f f o r t s to use independent short duration storms as the design c r i t e r i a for erosion structures. This procedure i s a t t r a c t i v e since the long term d a i l y meteorological records can be analysed s t a t i s t i c a l l y (Soulis and Vincent, 1977) but since storm sequence and timing are not accounted for, the res u l t s may not be r e a l i s t i c . Unfortunately, i n s u f f i c i e n t independent and separable events were recorded throughout the summer season to show the expected trending in basin response. Of some importance i s that the most s i g n i f i c a n t r a i n f a l l event of the year, which occurred i n early August, s o l i c i t e d no response from any of the recorders while very minor r a i n f a l l s i n June produced d i s t i n c t flood peakes. It would appear, based on the possib-i l i t i e s for large c a p i t a l savings implied by the observations that further work i s j u s t i f i e d i n defining the necessary parameters and the manner i n which they trend through the summer season, thus a f f e c t i n g the design s t a t i s t i c s . 4.1 THE NEXT STEP The Chick Lake study has indicated that the t y p i c a l modelling approach for small basins i s incorrect since c a l i b r a -tion i s based on single independent events. An appropriate model would have to take into account the systematic and random changes i n the basin c h a r a c t e r i s t i c s as well as the super-position of adjacent events. Since there i s a cert a i n random "wander" i n basin parameters due to conditions beyond the resolution of common measurements, an appropriate model might consist of elements d e t e r m i n i s t i c a l l y modelled, but each element described by a d i s t r i b u t i o n rather than a single number. Further, those elements which follow a time trend change should do so and the outcome should r e f l e c t these changes. Is t h i s e f f o r t worth i t ? If we can show that v i r t u a l l y a l l r a i n f a l l s early i n the summer, for instance, perhaps a single event c a l i b r a t i o n plus a s t a t i s t i c a l analysis of early season storms i s a l l that i s j u s t i f i e d . If the character of the r a i n events also change with time during the season, then t h i s also should be taken into account. Analysis of storm -45-d i s t r i b u t i o n based on 30 years of d a i l y records at Norman Wells shows that t h i s i s not apparently the case (see Figure 11). The d i s t r i b u t i o n s of storm s t a r t s , volume, and in t e n s i t y appear quite consistent; even when combinations of events are considered. Thus, the trending in basin response due to the lowering of the fr o s t table w i l l i n fact j u s t i f y the e f f o r t i n designing an appropriate model which can be calibrated on a minimum of data or f i e l d measurements and i s simple enough to allow the generation of flow s t a t i s t i c s by routing the a v a i l -able h i s t o r i c a l meteorological record through i t . A cursory look at summer records of p r e c i p i t a t i o n as compiled over t h i r t y - f i v e years at Norman Wells i l l u s t r a t e s the point. In no respect do the size of frequency of events trend, as i l l u s t r a t e d i n Figure 11. This implies that the storm event or combination of events of a given exceedence l e v e l , applied to a basin model of fixed parameters w i l l lead to excessively conservative r e s u l t s . This conclusion i s based on the concept that the available flow data and thus the model c a l i b r a t i o n tends to be from early i n the year when data . i s easiest to acquire because the response c h a r a c t e r i s t i c s are most severe. The framework for the appropriate model already exists i n the form of the Clark's model used for data analysis i n t h i s study. This model i s s u f f i c i e n t l y simple that even with exten-sions to allow trending i n parameters, including basin storage, i t should be reasonably e f f i c i e n t i n terms of computer use. Furthermore, a random element can be introduced to allow for natural uncertainty i n data and c h a r a c t e r i s t i c s . This type 60r t> SO ^ AO to 20 % 10 / M J J A § PLOTS WEPE EXTRACTED PROM DAILY METEOROLOGY S . ' OBSERVAT/ONS A T NORMAN WELLS, PROM J943-+ /977 3 -> ~ — — _ -/O DAY MOV/A ^ . . - ' CLEARER \ ^ -A STORM /S SEPARATED / CONSIDERED AN /A/DEPENDENT % i • / EVENT /F ^T L E A S T OA/E 'DRY'DAY SEPARATES /T / ' PROM SMOTHER EVE/VT fSOUL/S * 1//NCENT /977) « o v ! / - ~ / - 6 / 0 STORMS WERE OEF/A/EP AS /A/OEPENOSiVT 'SOMME/Z ^. ' RAMFALt EVENTS oyaG 7 % T YEAPS ANALYZED ^ L — i i i i L A/8: WHILE MILD TRENDS IN STORM CHARACTERISTICS ARE M J J A S EVIDENT, THEY ARE NOT STRONG ENOUGH TO JL/STF/ EITHER A FIXED PARAMETER OR A RAM EVENT BASED STATISTCAL APPROACH FIGURE //: INVESTIGATION OF TRENDS IN SUMMER STORMS AT NORMAN WELLS -47-of model could be run on long term meteorological records and used to d e t e r m i n i s t i c a l l y produce synthetic flow records from which design s t a t i s t i c s could be extracted. A model for south-ern use (non-trending parameters) incorporating uncertainty in basin c h a r a c t e r i s t i c s at the time of the event has been designed by Russell (1977) for estimating flow s t a t i s t i c s for municipal design. This technique has some advantage i n that some f l e x i b i l i t y i s allowed since, with further work, estimates of basin para-meters and t h e i r trends should be possible with r e l a t i v e l y few f i e l d measurements. Uncertainty i n these estimates can be introduced into the random nature of the parameters while the required r e a l data, the r a i n f a l l sequence, can be trans-ferred using the more complete available knowledge of the weather patterns. The re s u l t i n g long term hydrograph, while not l i k e l y correct i n absolute terms, should be s t a t i s t i c a l l y reasonable and provide some basis for a r a t i o n a l s t r u c t u r a l design. Clark's model, about the simplest r a i n f a l l - r u n o f f model available, takes account of both t r a v e l time and storage and has been widely used ( i t i s the basis of the U.S. Corps of Engineers HEC-1 program (HEC-1973)). Lacking anything better i t i s suggested that peak flows be computed on the basis of seasonal modelling of the runoff using, as input, r a i n f a l l data from the nearest long term meterological station (Norman Wells would have to serve for a wide area) either on a d a i l y basis or shorter time period i f suitable data are available. - 4 8 -(1) Keep a running t o t a l of storage space - evaporation less r a i n f a l l losses (to t a l r a i n f a l l less the e f f e c t i v e r a i n -f a l l which contributes to runoff) assuming that the storage space i s f u l l at the end of the snowmelt season. (2) Model the runoff using Clark's method when there i s a r a i n f a l l surplus after f i l l i n g the space created by evapor-ation, assuming: (i) "Losses equal s p l i t between i n i t i a l loss and constant rate i n f i l t r a t i o n loss (these losses should completely f i l l the storage space at the time). ( i i ) T i n hours = L /V + L /V c o/ o c c where L Q = length of overland flow (m) V Q = v e l o c i t y of overland flow (m/hr) V Q = 250 S where S = mean slope L c = channel length i n m V c = channel v e l o c i t y i n m/hr computed from Manning's or other standard formula. ( i i i ) R i n hours = 2T c The above procedure should y i e l d flow hydrographs for the s i t e i n question. From these, annual peaks could be abstracted and anlayzed by standard frequency methods. To allow for uncertainty the hydrologist may wish to put bounds on his assumed parameters and incorporate these i n the analysis by a procedure such as that Outlined by Russell (1977) . -49-5 . 0 CONCLUSIONS The C h i c k L a k e s t u d y was i n t e n d e d p r i m a r i l y as a l e a r n i n g e x e r c i s e r a t h e r t h a n a d e f i n i t i v e d a t a g a t h e r i n g s t u d y . The how a n d why o f t h e s u b a r c t i c h y d r o l o g y o f a p a r t i c u l a r t e r r a i n t y p e was t h e s u b j e c t , a n d i n t h i s r e s p e c t t h e s t u d y was a t l e a s t a p a r t i a l s u c c e s s . The d i f f i c u l t i e s o f g a t h e r i n g m e a n i n g f u l d a t a u n d e r h a r s h c o n d i t i o n s a r e d i s c u s s e d a t l e n g t h i n t h e A p p e n d i x w h i c h i s i n t e n d e d as a g u i d e a r o u n d t h e m a j o r d i f f i c u l t i e s a n d a d i r e c t o r y o f e v e n t s w h i c h a f f e c t t h a t r e m o t e d a t a g a t h e r i n g s t u d y . D e t e r m i n i n g w h a t t o m e a s u r e a n d why when d e a l i n g w i t h b a s i n s o f m u s k e g v e g e t a t i o n t y p e s i n t h e d i s c o n t i n u o u s p e r m a -f r o s t z o n e was a n e c e s s a r y p a r t o f t h e o v e r a l l s t u d y w h i c h i n i t i a t e d t h e w o r k a t C h i c k L a k e s i m p l y b e c a u s e n o r t h e r n h y d r o l o g y i s s t i l l i n i t s i n f a n c y r e l a t i v e t o t h e . s t u d y i n m o r e t e m p e r a t e c l i m e s . Some o f t h e q u e s t i o n s w h i c h i n i t i a t e d t h e s t u d y , t h e a n s w e r s o f w h i c h i n e v i t a b l y r e s u l t e d i n f u r t h e r q u e s t i o n s w e r e as f o l l o w s : (a) I s p e r m a f r o s t i m p o r t a n t ? (b) To w h a t e x t e n t i s b a s i n r e s p o n s e a f f e c t e d b y t h e p r e s e n c e o f p e r m a f r o s t ? (c ) What p r o c e s s e s o f t h e p e r m a f r o s t r e g i m e a r e h y d r o l o g i c a l l y i m p o r t a n t ? (d) What m i s c o n c e p t i o n s o f t h e n o r t h e r n e n v i r o n m e n t do we l a b o r w i t h ? As a l l u d e d t o , t h e e x i s t e n c e o f p e r m a f r o s t i s i m p o r t a n t , p a r t i c u l a r l y t h e t h a w p r o c e s s a n d t h e m a t e r i a l c o m p o s i t i o n o f -50-the active layer. If t h i s layer i s composed of an organic mat which behaves l i k e a sponge whose thickness increases with time, then basin parameters change and these changes must be taken into account. Also, since the point lowering of the f r o s t table i s highly variable, l o c a l lows are formed i n the table where moisture accumulates which reduces the in s u l a t i n g value of the cover further increasing the ;rate of progress of the f r o s t table. Thus the topography of the f r o s t table becomes an exaggerated r e p l i c a of the surface unless some form of discontinuity i s caused by surface disturbance. This creates increasing depressional storage and can also change the basin d e f i n i t i o n with time. Evaporation has occasionally been ignored when ca l c u l a t i n g a water balance i n the north, p a r t i c u l a r l y i f a close look at the amounts of water involved has been avoided. While t o t a l evaporation i s not large (300 mm estimated for Chick Lake) when compared with the limited annual p r e c i p i t a t i o n (approximately 330 mm at the study site) about half of which f a l l s as snow,-it becomes important. This i s p a r t i c u l a r l y true since i t can be shown that the r e a l evaporation approaches the pot e n t i a l evapor-ation i n organic t e r r a i n units since the water table cannot f a l l far below the surface due to the location of the f r o s t table, and a constant wicking action of the a l l important organic mat. Again, why i s evaporation important? It appears to act as a secondary drainage mechanism which removes water from the surface cover, thus creating pot e n t i a l storage for incoming p r e c i p i t a t i o n . The more storage that i s available, the less -51-s i g n i f i c a n t the basin response. Where does t h i s a l l lead? Simply, the i n t e l l i g e n t design of minor hydraulic structures and erosion control works i s generally based on some acceptable l e v e l of f a i l u r e r e l a t i v e to the costs and r i s k s of damage. The s i z i n g therefore, i s based on some form of s t a t i s t i c a l analysis which provides a design flow of small return period floods. Unfortunately, i n northern latitudes both flow data and experience i s i n short supply, with the meteorological data s i t u a t i o n being only somewhat better. The simplest approach to define the design flood i s to define a single set of basin parameters and choose the storm event of the required s t a t i s t i c a l l e v e l and route t h i s through the fixed basin model. However, since i t has been shown that the basin parameters change s i g n i f i c a n t l y with time, a l l storm events must be considered. It has been further demonstrated that even for small basins the hydrologic response i s atten-uated to the extent that the storm hydrographs overlap and thus event combinations must be considered. Thus, to define the necessary design hydrographs, the design model must allow the basin parameters to vary with time, must take into account antecedent conditions, and must allow the superposition of adjacent events. F i n a l l y , i t has been shown that the storm series, based on the Norman Wells record, are not s u f f i c i e n t l y skewed to early summer to j u s t i f y accepting the common design approach. This approach, generally based on a single basin c a l i b r a t i o n obtained early i n the year and then applied to a l l storm events regardless of t h e i r timing tends to conservatively -52-e s t i m a t e s i n g l e e v e n t p e a k s , b u t i g n o r e s , a n d t h e r e f o r e i s s e r i o u s l y u n c o n s e r v a t i v e w i t h r e s p e c t t o e v e n t s u p e r p o s i t i o n . A s i m p l e m o d e l , b a s e d o n t h e C l a r k m e t h o d o f h y d r o g r a p h s y n t h e s i s ( s e e G r a y , 1970 a n d HEC, 1973) i s p r o p o s e d w h i c h c o u l d be s e t up t o a l l o w b o t h r a n d o m a n d s y s t e m a t i c c h a n g e s i n b a s i n p a r a m e t e r s . Use o f a s i m p l e m o d e l a l l o w s a l a r g e a m o u n t o f m e t e o r o l o g i c a l d a t a t o b e u t i l i z e d t o p r o v i d e t h e f l o w s t a t i s t i c s . An e x t e n s i o n o f t h e p r o c e s s i n v o l v e s t h e i n p u t o f b a s i n p a r a m e t e r s as r a n g e s ( o r f o r t i m e v a r y i n g i n f o r m a t i o n as b a n d s ) a n d b y u s i n g t w o o r t h r e e s p e c i f i c v a l u e s f r o m t h e r a n g e a n d c a l c u l a t i n g f l o w b a s e d o n e a c h c o m b i n a t i o n o f t h e p a r a m e t e r s , a l a r g e s e t o f s t a t i s t i c a l l y s i g n i f i c a n t f l o w p e a k s a r e g e n e r a t e d ( s e e R u s s e l l , 1 9 7 6 ) . To u t i l i z e t h i s m e t h o d t h e m a n n e r i n w h i c h t h e p a r a m e t e r s c h a n g e m u s t be d e f i n e d . Of p a r t i c u l a r i n t e r e s t a r e t h e s p a t i a l a n d t e m p o r a l v a r i a t i o n o f t h e l o w e r i n g o f t h e f r o s t t a b l e a n d t h e e v a p o r a t i o n r a t e as a f u n c t i o n o f d e p t h t o t h e w a t e r t a b l e a n d d a t e . C h a n g e s i n m o d e l p a r a m e t e r s s u c h as t h e v a r i a t i o n o f t i m e o f c o n c e n t r a t i o n a n d s t o r a g e c o e f f i c i e n t w i t h t h e d e p t h o f t h a w a n d w a t e r t a b l e a n d / o r m o i s t u r e c o n t e n t o f t h e s u r f a c e c o v e r m u s t b e i n v e s t i g a t e d . To e x a m i n e a n d d e f i n e t h e s e c o n c e p t s f u r t h e r , d e t a i l e d s t u d i e s a r e r e q u i r e d , i n c l u d i n g e x t e n s i v e f i e l d w o r k . The d e f i n i t i o n o f t h e s e m e c h a n i s m s w i l l l e a d t o a b e t t e r u n d e r s t a n d i n g o f n o r t h e r n h y d r o l o g y as w e l l as r e d u c i n g t h e " c o n s e r v a t i v e n e s s o f i g n o r a n c e " w h i c h i s c o s t l y b o t h i n t e r m s o f money a n d e n v i r o n m e n t a l damage r e s u l t i n g f r o m o v e r d r a i n a g e b y t h e o v e r s i z i n g o f d r a i n a g e s t r u c t u r e s f o r n o r t h e r n - 5 3 -c o m m u n i t i e s a n d t r a n s p o r t a t i o n l i n k s . -54-BIBLIOGRAPHY AES. Monthly Records of Meteorological Observations i n Canada. Fisheries and Environment, Atmospheric Environment Service. Ottawa. 1972-1977. Bredthouer, D. of CRREL, Fairbanks, Alaska. Personnal Commun-ic a t i o n . NRC Conference on Cold Regions Hydrology. Vancouver, B.C. 19 79. Brown, R.J.E. Permafrost Terminology, Technical Memorandum  Associate Committee on Geotechnical Research, National Research Council of Canada, No. I l l , Ottawa Publications Section, NRC, 1974, pp 62. Burns, B.M. The Climate of the Mackenzie Valley-Beaufort Sea. Vol. 1, Climatological Studies, No. 24. Atmospheric Environment Service, Environment Canada. Ottawa, 19 73, pp 227. Carlson, C.E. of the University of Alaska, Fairbanks. Personnal Communication. NRC Conference on Cold Regions Hydrology. Vancouver, B.C. 1979. Clark, CO. Storage and the Unit Hydrograph, Trans. ASCE, Vol. 110, 1945, pp 1419-1488. Dingman, S.L. Hydrology of the Glen Creek Watershed, Tanana River Basin, Central Alaska. U.S. Army Corps of Engineers, CRREL Res. Rpt. 297, 19 71. Douglas, R.D. Senior b i o l o g i s t with Renewable Resources Ltd. of Edmonton. Personnal Communications at Chick Lake. 1977. G i l l , D. of the University of Alberta, Edmonton. Personnal Communication. 1979. Gray, D.M. Handbook on the P r i n c i p l e s of Hydrology. Canadian Contribution to IHD, Fisheries & Environment Canada. 1970, pp.390. Hare, F.K. and M.K. Thomas. Climate Canada. Toronto: Wiley, 1974, pp 256. HEC. HEC-1 Flood Hydrograph Package. Hydrolic Engineering Centre, U.S. Corps of Engineers, Davis C a l i f o r n i a , 1973. Hydrological Atlas of Canada. prepared by Fisheries and Environment Canada, available from Supply and Services Canada, Ottawa, Ontario, Canada, 1978. Newbury, R.W. River Hydrology i n Permafrost Areas, Proceedings  of Workshop Seminar on Permafrost, CNC/IHD, Calgary, Alberta, February 19 74. -55-Rahn, P. and M.T. Giddings. Constructing a Temporary Stream  Gauging Station, C i v i l Engineering 37 (12) pp 46-47. Russell, S.O. A Method for Computing Design Flows for Urban  Drainage, Proceedings of Canadian Hydrology Symposium Edmonton, Alberta (1977) Sept. 1979. Soulis, E.D. and D.E. Reid. Impact of Interrupting Subsurface  Flow i n the Northern Boreal Forest. Proceedings of the Third International Conference on Permafrost, Edmonton Alberta, (1978) July. Soulis, E.D. and D.G. Vincent. Individual Storm S t a t i s t i c s  from Daily R a i n f a l l Records, Proceedings of the Second AMS/CMOS Conference on Hydrometeorology, Oct 77, Toronto. Thornthwaite & Mather. The Water Balance. Drexel Ins t i t u t e of Technology, Laboratory of Climatology, Publications in Climatology, Vol 8, No. 1, 19 49. Williams, G.P. The Thermal Regime of a Sphagnum moss Peat Bog, Proceedings of the Third International Peat Congress, Quebec August 1968, pp 195-200. APPENDIX: NORTHERN FIELD OPERATIONS - 5 7 -NORTHERN F I E L D OPERATIONS I n a n o r t h e r n d a t a g a t h e r i n g p r o g r a m t h e r e a r e a n u m b e r o f c o n s i d e r a t i o n s g e n e r a l l y o u t s i d e t h e u s u a l r e a l m o f e x p e r i e n c e o f many f i e l d p e r s o n n e l . The comments w h i c h f o l l o w a r e a c o l l e c t i o n o f s u g g e s t i o n s a n d c o n s i d e r a t i o n s b a s e d o n e x p e r i e n c e s w h i c h may b e o f u s e t o t h e f i r s t t i m e n o r t h e r n e r i n t h e p l a n n i n g o f a p r o g r a m , p r e s e n t e d b r i e f l y i n p o i n t f o r m . 1. T r a n s p o r t a t i o n - a i r f r e i g h t c o s t s a r e h i g h a n d o f t e n t h e o n l y a l t e r n a t i v e , b u t g i v e n s u f f i c i e n t l e a d t i m e o v e r l a n d o r w a t e r t r a n s -p o r t c a n be u s e d t o a d v a n t a g e . - f r e i g h t l e a p - f r o g g i n g i s u s e f u l . ( i e : t r a n s p o r t b y r e l a t i v e l y c h e a p means as f a r as p o s s i b l e i n o r d e r t o r e d u c e t h e e x p e n s i v e j u m p t o t h e s i t e . e g : b a r g e t o a n e a r b y p o i n t a n d t h e n s l i n g i n u s i n g a h e l i c o p t e r . ) a) A i r c r a f t F i x e d W i n g - c h e a p e r , f a s t e r a n d g e n e r a l l y l a r g e r c a p a c i t y t h a n h e l i c o p t e r s . - a w k w a r d s h a p e s a n d s i z e s d i f f i c u l t b e c a u s e o f t h e l i m i t a t i o n s o f d o o r s . - s p r i n g a n d f a l l u s e f u l n e s s s o m e t i m e s l i m i t e d s i n c e i c e c o n d i t i o n s l i m i t f l o a t a n d s k i a c c e s s a n d t e m p o r a r y s t r i p s a r e o f t e n u n u s e a b l e due t o f r o s t h e a v e s o r s o f t g r o u n d . - u s e a b l e f o r r e c o n n a i s a n c e b u t t h e i n a b i l i t y t o l a n d a t w i l l , f l y l o w a n d - 5 8 -slow or hover reduce t h e i r value. Helicopters - expensive - f u e l i s a problem; high consumption and limited tankage require careful planning and possible f u e l caches. - the correct machine w i l l handle almost any fr e i g h t as doors are better placed or items can be slung below. Further, the f r e i g h t can be placed p r e c i s e l y where i t i s wanted. - useful as a construction tool - sky hook. - probably the best reconnaisance vehicle available as cabin v i s i b i l i t y i s excellent, personnel can be put almost anywhere, and the hover c a p a b i l i t y i s most useful. b) Boats - for moving heavy f r e i g h t , barges and tugs can be used i n the Mackenzie Valley but lead time of almost a f u l l year i s necessary. - canoes, j e t boats and other small c r a f t are useful for moving small amounts of f r e i g h t , water sampling programs, etc. and t h e i r a v a i l a b i l i t y i s generally good. - 5 9 -c) O v e r l a n d - w i t h t h e o p e n i n g o f t h e D e m p s t e r H i g h w a y t o I n u v i k a n d t h e c o n s t r u c t i o n o f t h e M a c k e n z i e H i g h w a y , t h i s p o s s i b i l i t y i s b e c o m i n g m o r e v i a b l e . C o n t a c t t h e D e p a r t m e n t o f P u b l i c W o r k s i n E d m o n t o n f o r a c c e s s a n d c o n d i t i o n s . - i n w i n t e r t h e w i n t e r r o a d n e t w o r k may b e o f u s e b u t w i l l r e q u i r e i n v e s t i g a t i o n b y t h e p l a n n e r . O f t e n t h e f r o z e n w a t e r w a y s become t h e h i g h w a y s o f t h e n o r t h . - i n summer o v e r l a n d t r a n s p o r t o f f t h e a l l - w e a t h e r r o a d s i s d i f f i c u l t a n d d i s c o u r a g e d d u e t o t h e damage t o t h e f l o r a . 2 . I n s t r u m e n t a t i o n - c h o i c e becomes c l o s e l y a l i g n e d w i t h t h e mode o f t r a n s p o r t a v a i l a b l e ; a c h o i c e o f t e n b e y o n d t h e m a n i p u l a t i o n o f t h e p l a n n e r . - m u s t be s i m p l e , r o b u s t a n d v e r y r e l i a b l e . T h e r e a r e v e r y f e w r e p a i r f a c i l i t i e s i n t h e n o r t h . - f r e i g h t h a n d l e r s a r e n o t t e n d e r w i t h b o x e s ; n e i t h e r a r e t h e o c c a s i o n a l b e a r o r moose o n c e an i n s t r u m e n t i s i n t h e f i e l d . - b e f o r e a n y t h i n g g o e s i n t o t h e f i e l d i t m u s t be a s s e m b l e d a n d c h e c k e d . - s u i t a b l e s p a r e p a r t s s h o u l d go w i t h e a c h u n i t . - e v e r y e f f o r t m u s t be made t o e n s u r e t h a t f i e l d p e r s o n n e l a r e f a m i l i a r w i t h how t h i n g s w o r k i n o r d e r t o e f f e c t r e p a i r s o r i m p r o v i s e when n e c e s s a r y . the environment i s extreme; therefore weatherproof the instruments ( r i g i d foam boxes) and mount them well. Again bear and moose present a problem. care must be taken not to provide nesting s i t e s for the birds, animals and insects i n the instruments. There-fore screen or plug openings where possible, mechanical drives for charts seem to work better than e l e c t r i c a l ones. They don't have batteries to freeze which can be forgotten on a service t r i p and they tend to " t i c k " loud enough that there i s some assurance the unit i s working after being placed i n i t s weatherproof box. use l o t s of desicant; preferably one pouch i n each instrument of the variety that changes color as i t s capacity i s used up. This provides a useful check, carry a general tool k i t , as well as s p e c i f i c parts anticipated to give problems, useful items to bring along: - fibreglass packing tape - epoxy glue - quart of resin, some fibreglass c l o t h and catalyst - push-type hand d r i l l - nuts, bolts, some metal screws and n a i l s - hack saw blade, axe f i l e - axe - vice grips, p l i e r s with wire cutters, crescent wrench - 6 1 -- s p a r e e l e c t r i c a l l e a d - • b a i l i n g w i r e - t h e s e i t e m s a l o n g w i t h t h o s e i t e m s d e f i n i t e l y r e q u i r e d f o r s e r v i c i n g o r i n s t a l l a t i o n s h o u l d be t a k e n . - How i s t h e i n s t r u m e n t a t i o n t o be i n s t a l l e d ? I s i t a r e a s o n a b l e s e t - u p g i v e n t h e t o o l s a n d s i t e c o n d i t i o n s ? P a c k i n g a n i t r o g e n b o t t l e t h r o u g h a swamp i s n o t p l e a s a n t , h o w e v e r i t becomes r e a s o n a b l e i f a h e l i c o p t e r i s a v a i l -a b l e t o l o n g l i n e p i e c e s i n t o a w k w a r d l o c a t i o n s . - f l o w r e c o r d e r s - O t t b u b b l e r r e c o r d e r s i n v o l v e t h e a b o v e m e n t i o n e d n i t r o g e n b o t t l e , p l a s t i c t u b i n g w h i c h m u s t be p r o t e c t e d f r o m m i c e , a f i n i c k y p e n a n d a b a t t e r y c h a r t d r i v e . - S t e v e n s F f l o a t - t y p e r e c o r d e r s a r e s i m p l e , r e q u i r e a m o r e e l a b o r a t e s t i l l i n g w e l l a n d a n o n - s e t t l i n g f o u n d a t i o n , b u t a r e v e r y r e l i a b l e . T h e y do h o w e v e r a l s o r e q u i r e f r e q u e n t s e r v i c e . - S t e v e n s A f l o a t - t y p e r e c o r d e r s w i t h a m e c h a n i c a l c h a r t d r i v e , a n d a 90 d a y s t r i p c h a r t p r o v e d t h e m o s t r e l i a b l e . O f p a r t i c u l a r i n t e r e s t i s t h e s i m p l e p e n d e s i g n w i t h a b a c k - u p p e n c i l t r a c e , a n d g o o d r e s o l u t i o n t h a n k s t o a r e v e r s i n g p e n d r i v e . - r a i n g a g e s - s t a n d a r d W e a t h e r M e a s u r e t i p p i n g b u c k e t g a g e s f i t t e d w i t h a m e r c u r y t y p e s w i t c h w o r k e d w e l l . 3 . E n v i r o n m e n t w e a t h e r - b e s t d e s c r i b e d as e x t r e m e , t h e a u t h o r h a s -62-experienced snow and freezing conditions i n a l l months, as well as a large insect hatch when there was 90% snow cover. Winter i s predictable - cold. s u r v i v i a l - go prepared; while a i r c r a f t are required to carry k i t s , they are occasionally neglected and often have been "raided". - an Arctic-type parka i s good insurance from October through May i n the Discontinuous Zone - a l l year further north. - a l l personnel take a good course which includes a i r c r a f t safety and f i r s t aid, carry the gear and play by the rules. insects - always carry insect repellent; i n p a r t i c u l a r l y bad conditions, gloves and a headnet are necessary combined with long sleeves and trousers, daylight - during summer i t i s often possible to work nearly 2 4 hours as far south as in. the northern extremes of the provinces. This can often be used to advantage during service t r i p s when the work i s l i g h t and the t r a v e l time between s i t e s i s long. - i n winter, the short day can seriously l i m i t access since f l y i n g time i s c u r t a i l e d , f l o r a - muskeg can be deceiving with respect to i t s apparent bearing capacity. - i n spring, when frozen, a l l i s well, while by summer instrumentation has been tumbled into a fen thanks - 6 3 -t o d i f f e r e n t i a l t h a w i n g a n d s e t t l e m e n t . - one s o l u t i o n : u s i n g an a u g e r , d r i l l t h r o u g h t o t h e p e r m a f r o s t a n d embed s t a k e s t o a c t as a p i l e f o u n d a t i o n . T h i s i s b e s t d o n e i n t h e f a l l s i n c e t h e d r i l l i n g i s e a s i e r , a c t i v e l a y e r i s m e l t e d , a n d t h e p i l e s w i l l be f r o z e n i n s o l i d o v e r t h e w i n t e r . - summer a c c e s s i s o f t e n d i f f i c u l t s i n c e t h e s u r f a c e i s v e r y s p o n g y . - a t t i m e s i n summer , t h e f i r e h a z a r d i s e x t r e m e a n d g r e a t c a r e m u s t be e x e r c i s e d . F i r e w i l l s p r e a d e v e n w i t h s t a n d i n g w a t e r a f e w i n c h e s b e l o w t h e t o p o f t h e moss l a y e r . - t h e g r o w t h r a t e o f w i l l o w a l o n g t h e r i v e r b a n k s i s i n c r e d i b l e a n d new g r o w t h c a n o b s c u r e f l a g g i n g , c l e a r i n g , e t c . i n w e e k s . Keep t h i s i n m i n d when f l a g g i n g a n d w r i t i n g s i t e d e s c r i p t i o n s , f a u n a - b e a r s , u n p r e d i c t a b l e , h a v e b e e n k n o w n t o d e s t r o y an i n s t r u m e n t s i t e f o r no a p p a r e n t r e a s o n . - moose o r c a r i b o o seem t o p r e f e r s e t u p s f o r s c r a t c h -i n g p o l e s , p a r t i c u l a r l y w h e r e t h e t r e e s a r e f e w o r s p i n d l y . - b u i l d p l a t f o r m s , e t c . w i t h t h i s i n m i n d . P r o t e c t t h e i n s t r u m e n t s i f p o s s i b l e . - s u r v e y f l a g g i n g o f t e n g e t s e a t e n b y m o o s e . S p r e a d l o t s a r o u n d a n d maybe some w i l l be l e f t . - p o l y e t h y l e n e r o l l s f o r b a s i n l i n e r s , i f l e f t on t h e g r o u n d , a r e g r e a t " c h e w s " f o r b e a r , w o l f a n d m i c e . Have e n o u g h t o a l l o w f o r t h e o u t e r l a y e r s - 6 4 -o f t h e r o l l t o be d a m a g e d . Once s p r e a d t h e a t t r a c t -i o n i s d i m i n i s h e d . - m i c e chew e l e c t r i c a l i n s u l a t i o n . T h e r e f o r e i n s t a l l w i r e t i g h t l y a n d p l a c e w i r e so i t w o n ' t s h o r t o r g r o u n d a n d d r a i n t h e b a t t e r y . 4 . C o m m u n i c a t i o n s - M o t o r o l a " l u n c h b o x " FM r a d i o s p r o v i d e e x c e l l e n t p e r s o n t o p e r s o n a n d g r o u n d t o h e l i c o p t e r c o m m u n i c a t i o n d u r i n g f i e l d o p e r a t i o n s . F u r t h e r , t h e u n i t c a n be s e t up f o r m u l t i p l e c h a n n e l s t o t i e i n t o t h e r a d i o t e l e p h o n e n e t -w o r k . Range i s l i m i t e d t o a b o u t 25 m i l e s l i n e o f s i g h t e i t h e r b e t w e e n u n i t s o r t o t h e r e p e a t e r s t a t i o n . - s h o r t wave c o m m u n i c a t i o n i s n e c e s s a r y f o r l o n g e r d i s t a n c e s w h e r e t h e l i n e o f s i g h t i s o b s t r u c t e d . W h i l e i t d o e s w o r k , i t s h o u l d o n l y be c o n s i d e r e d f o r s e m i - p e r m a n e n t camp o p e r a t i o n s s i n c e o p e r a t i n g s c h e d u l e s a r e r e q u i r e d a n d a b a s e s t a t i o n s h o u l d be m a i n t a i n e d . 5 . A c c o m m o d a t i o n - f l y camps a r e o f t e n c o s t l y t o s e t - u p , p a r t i c u l a r l y i n t e r m s o f t i m e l o s t t o w a r d s p r o g r a m o b j e c t i v e s . - p e r m a n e n t camps - D e p a r t m e n t o f P u b l i c W o r k s r u n s a s e r i e s o f camps f o r n o r t h e r n h i g h w a y c o n s t r u c t i o n a n d i s o f t e n h e l p f u l . - o i l c o m p a n i e s o p e r a t i n g i n t h e a r e a s o m e t i m e s a l l o w t h e i r d r i l l o r s e i s m i c camp f a c i l i t i e s t o be u s e d ; some g e n e r a l l y d i s c r e e t i n q u i r i e s a r e i n o r d e r . -65-- contact Lands and Forests, p a r t i c u l a r l y i f some connection to environmental concerns can be made by the investigation. - f i s h i n g and hunting camps - contact the t o u r i s t bureau. hotels, motels, etc. - check the major towns. There i s often some form of rental accommodation. small v i l l a g e s - a c a l l to the R.C.M.P. of the community can r e s u l t in either an i n v i t a t i o n to stay at the station or a lead to further i n q u i r i e s . Personnel - f i e l d experience i s important, p a r t i c u l a r l y remote experience. - f a m i l i a r i t y with equipment, f i r s t aid, s u r v i v a l s k i l l s . - p r a c t i c a l , innovative and open-minded. - healthy. Contingency - what happens i f things go wrong? Back-up i s important in northern operations. - plan for unexpected costs. As a rough guide i s to add 15 to 20% to estimated cost, excluding a i r c r a f t charges. Add a 30% contingency to those. - plan for l o s t time due to mechanical problems, schedul-ing d i f f i c u l t i e s and most of a l l weather. - back-up parts and spares are necessary items, but don't l e t them stop at the instrumentation. A pa i r of l o s t -66-per s c r i p t i o n glasses can be just as devastating to a program as a case of odd size dead batteries. - before you go north, ask the "what i f ? " questions to cover each aspect of the program and provide for a solution where possible. The foregoing i s a somewhat d i s j o i n t series of comments which w i l l hopefully provide a s t a r t i n g point i n planning; an operation which i s designed to eliminate uncertainty and cover possible events which may occur during f i e l d operations. Of necessity, any program i s a compromise of what can be accomplished with certainty, and what might be; a l l within the available budget. Perhaps the f i r s t question should be "Are we looking at the right source of information by going into the f i e l d ? " Once i t has been decided that f i e l d data i s necessary, the questions: "Is i t possible to get meaningful re s u l t s ? " and "How are we going to analyse the re s u l t s ? " must be answered so that a l l of the necessary data that i s required i s obtained. F i n a l l y , "Are we measuring the correct things; are there factors within t h i s unusual environment which should be measured?" (eg: "Is permafrost important?"). Program planning i s a series of answering the appropriate questions with the best possible solutions. Northern programs are inherently very expensive, but the f a i l u r e to plan properly, or to gather the correct information with the r i g h t equipment generally r e s u l t s i n economic disaster. It i s d i f f i c u l t and often impossible to "patch up" errors i n judgement when dealing with the north. 

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