Open Collections

UBC Undergraduate Research

An investigation into south campus storm water catchment and filtration technologies Zaka, Haider; Aassouli, Mustapha; Burton, Jeffrey; Noyes, Theo Apr 4, 2013

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
18861-Zaka_H_et_al_SEEDS_2013.pdf [ 1MB ]
Metadata
JSON: 18861-1.0108488.json
JSON-LD: 18861-1.0108488-ld.json
RDF/XML (Pretty): 18861-1.0108488-rdf.xml
RDF/JSON: 18861-1.0108488-rdf.json
Turtle: 18861-1.0108488-turtle.txt
N-Triples: 18861-1.0108488-rdf-ntriples.txt
Original Record: 18861-1.0108488-source.json
Full Text
18861-1.0108488-fulltext.txt
Citation
18861-1.0108488.ris

Full Text

UBC Social Ecological Economic Development Studies (SEEDS) Student Report       An investigation into South Campus Storm water Catchment and Filtration Technologies Haider Zaka, Mustapha Aassouli, Jeffrey Burton, Theo Noyes  University of British Columbia APSC 262 April 4, 2013           Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report”.  An investigation into South Campus Storm water Catchment and Filtration Technologies             Team members: Haider Zaka, Mustapha Aassouli, Jeffrey Burton, T heo No yes                 University of British Columbia APSC 262 April 4, 2013 Dr. Paul Winkelman   ii  ABSTRACT  In this report, research concerning  the possibilit y of capturing rainwater for use at the UBC Farm during the dry months of the year was conducted. Currently, the UBC Farm relies on the Cit y of Vancouver for most of its water needs, and the prices during the peak season (summer) can get ver y expensive. However, since water usage during said season is also at its peak, the total cost is very high. T herefore, a solution to tackle the problem of reliance on city water is needed.   T he current infrastructure at the UBC Farm allows for many soluti ons to be implemented for solving this issue. T he constraints that had to be taken into account had to do with how easy is it to maintain a certain solution, and how expensive is it to implement. As for assumptions, it was assumed that there is enou gh spac e to build, for example, a cistern, or a wet pon d. T hese assumptions were verified by visiting the Farm and asking employees for information about available space, as well as infrastructure. T o come up with adequate solutions, many studies done by several universities were consulted, as well as systems that were proven to work on the field that were built by users across the globe. Many manufacturers’ websites were also used for research, but t his was limited to filters that can be used in conju nction with other solutions. T he main three studies that were taken into account, and that were discussed in this report, include an underground detention system for rainwater that was collected from parking lots, a system that used rooft ops as a mean of catching rain water then passed it through a chain of filters all the way int o a detention tank or cistern. T hen a wet pond solution for catching any rainwater that is flowing on the grou nd which also incorporates natural filtering of the water. It was fou nd that all th ree solutions can introd uce considerable savings in water usage during the peak season, ho wever, the most cost effective and easy to implement solution is the wet po nd. T his solution will work quite well since the UB C Farm already has space in which a wet pon d can be built, and the groun d is sloped towards it which also minimizes any landscape changes.   More research was done to validate whether the wet pond is the ideal solution, and it was fou nd that the latter can save the UBC Farm a total $12, 0 00 for the entire lifetime of the wet po nd which is about 25 years. T hus it is recommended that the wet pond solution be implemented because it meets all the constraints, and it will also help the UBC Farm save a considerable amount of money, while also decreasin g its reliance on water from the Cit y of Vancouver.       iii  Table of Contents A B S TR A C T  ................................ ................................ ................................ ................................ ......  ii L IS T OF IL L U S TR A TIO N S  ................................ ................................ ................................ .............  iv  G L O S SA R Y  ................................ ................................ ................................ ................................ ..... v  L IS T OF ABB R EV IA TIO N S  ................................ ................................ ................................ ............  vi  1 .0 INTR ODUCTIO N  ................................ ................................ ................................ ......................  1  2 .0 CUR RE N T STA TE OF UBC FAR M  ................................ ................................ .........................  2  2.1 Overview of the UBC Farm’s Water Supply ................................ ................................ .........  2  2 .2    UBC Farm’s Water Usage and Expenditures ................................ ..............................  2  2 .3 Current Infrastructure  ................................ ................................ ................................ ............  3  3 .0 CAS E STUDY OF AN  UNDERGR OUND DETAIN ME N T AND FIL TR A TIO N  SYS TE M  ........  5  3 .1 Metho d olog y and Results  ................................ ................................ ................................ .....  5  3 .2 Environmental Assessment  ................................ ................................ ................................ ..  6  3 .3 Societal Assessment  ................................ ................................ ................................ .............  6  3 .4 Economic Assessment  ................................ ................................ ................................ ..........  7  3 .5 Summary  ................................ ................................ ................................ ...............................  7  4 .0 POTE N TIA L W ETL A NDS FOR UBC FAR M  ................................ ................................ ............  8  4 .1 Overview and Principles of Operation  ................................ ................................ ..................  8  4 .2 Design Requirements  ................................ ................................ ................................ ...........  8  4 .3 Effectiveness of Wet Pon ds as a Filtration and Catchment Technique  ...............................  8  4 .4 Societal, Environmental, and Economic Analysis  ................................ ................................  9  4 .5 Summary  ................................ ................................ ................................ .............................  11  5 .0 CAS E STUDY: METH OD FOR W ATE R CATC H ME N T USIN G ROO F ARE A  .....................  12  5 .1 Metho d olog y and Results  ................................ ................................ ................................ ...  12  5 .2 Environmental Assessment  ................................ ................................ ................................  17  5 .3 Societal Assessment  ................................ ................................ ................................ ...........  17  5 .4 Economic Assessment  ................................ ................................ ................................ ........  17  5 .5 Summary  ................................ ................................ ................................ .............................  18  6 .0 CON CL U S ION AND RECOMME NDATION  ................................ ................................ ...........  19  R E F ER E N CE S  ................................ ................................ ................................ .............................  20  A P P ENDIX A ................................ ................................ ................................ ................................ .  21   iv    LIST OF ILLUSTRATIONS  Figure 2.1 Seasonal Water Consumption of UBC Farm......... ... .... .... ... .... ... .... ... .... ... . ..... ... . ... .... .. . 2  Figure 2.2 Seasonal Water Expenditures of UBC Farm......... ... .... .... ... .... ... .... ... .... ... . ..... ... . ... .... .. . 3  Figure 2.3 To p o graphical Map of UBC Farm Including wetland areas....... .... .... ... .... . ..... ... .... ... . . . . 4  Figure 3.1 Example of an undergroun d storage tank......... ... .... ... .... .... ... .... ... .... ... .... . ..... ... .... .... . . . 5  Figure 4.1 Effectiveness of Wet Pon ds as a filtration technique...... .... .... ... .... ... .... .. . .. ..... ... .... ... . . . 9  Figure 4.2 Water Expenditure Projections for UBC Farm........ ... .... ... .... .... ... .... ... .... ... . ..... ... ... . ....1 0  Figure 5.1   A simple system to redirect runo ff water to plants...... ... .... .... ... . . .. ... .... ... .. ..... ... .... ....1 2  Figure 5.2   A complex system to catch, treat, store, and distribute ra in water... ... .... .. ..... ... .... ....1 3  Figure 5.3  Har vest Hut at the UBC Farm. Approximate roof area is  100m2 ......... ... .. ..... ... .... ....1 3  Figure 5.4  Farm Center at the UBC Farm. Approximate roof area is 216m2........ ... .. ... .. ... ... . .... 1 4  Figure 5.5  Farm Center at the UBC Farm. A view of the gut ters a nd drainpipes....... .. ... ... .... .... 1 5  Figure 5.6  A FlotenderTM Grey Water Machine........ .... ... .... ... .. .. .... ... .... ... ... . ... .... ... .. ..... ... .... .... . 1 5  Figure 5.7  A sample of cistern manufactured by BarrTM Plastics.... .... ... .... ... .... ... .... . .... . ... .... .... 1 6  Figure 5.8  A cistern built in - h o use. Courtesy of The Gulf Islands  Rainwater Con nection Ltd ... 1 6                           v     GLOSSARY  Detainment T he act of holding water for a set period of time which is usually short.  Catchment Collecting  and containing water for further use .  Filtration Removing pollutants and/or particles from water or any other substance.  Storm Water An abnormal amount of surface water often due to heavy rain or a snowstorm.  Grey water Wastewater generated from domestic activities such as laundry, dishwashing, and bathing,  which can be recycled on - site for uses such as landscape irrigation and constructed wetlands.                                 vi       LIST OF ABBREVIATIONS  UBC The University of British Columbia  GVRD Greater Vancouver Region District                                  1   1.0 INTRODUCTION  T he University of British Columbia is known as a living lab. T his makes the entire campus a space for experimenting wit h sustainable projects. If the experiment succeeds and provides an efficient and sustainable approach to collect, filter and reuse water, the university will become a leading example for a larger audience even outside the campus walls.   Currently the university storm water management sy stem has four catchment areas on campus. T hese are targeted locations where rain water flows from a higher to lower elevation and the collected water ends up at the city of Vancouver’s water filtration system. By making use of a water catchment and filtrat ion system to reuse rainwater in watering plants, the university can reduce chances of flood since the cisterns can also be used as a detention tank . Moreover, the soil erosion on campus can be reduced and the overall sustainable image of UBC will be lifte d.   UBC is not part of the city of Vancouver which means the city laws do not necessarily apply on campus. T his allows the university to freely experiment with new technologies in order to promote sustainabilit y. T he stakeholders for this project include t he students, facult y and staff members of UBC, the residents, the UBC Farm and UBC Utilities.   Currently the UB C farm gets water from the city of Vancouver. However, the farm would like to investigate the possibilit y of making use of a storm water  catchmen t and filtration system. This is partially due to the fact that even though it rains a lot in Vancouver, the farm is still dry for three months during the summer. T his is due to water shortage from the city water supply.    Af ter speaking in person with some of the UBC Farm staff, it seems that the farm needs a simple to install and use, easy to maintain and a cost effective solution. T his report will discuss three different case studies on various technologies used to collect and use storm water.  T his re port will discuss the social, economic and environmental impacts of each individual technolog y. A recommended solution for the UBC Farm is also enclosed in this report, along with specific reasons as to wh y the chosen solution is most feasible compared to the other methods presented.       2   2.0 CURRENT STATE OF UBC FARM  2.1 Overview of the UBC Farm’s Water Supply          UBC Farm is looking to up date where it attains its water for agriculture. Currently UBC Farm is acquiring its water from the Greater Van couver Region District’s (GVRD) main water supply. So far this has worked fine but UBC Farm would like to assess the possibilit y of using storm water runof f for irrigation. T his has multiple benefits: potentially, it can benefit the farm economically; the farm can save money on water both during the peak season and also off season. Using storm water runof f is environmentally friendly. Storm water is generally considered waste water and runs into storm drains which run off into Vancouver’s water filtration s ystem. If the runof f was instead used to water plants, this would be less wasteful and also lower the load on Vancouver’s water filtration system. Finally, implementing storm water filtration and catchment fits in with UBC Farm’s philosophy of self - sustain abilit y; they would be self -reliant and that would benefit the community’s self - image.   2.2    UBC Farm’s Water Usage and Expenditures           Currently, UBC Farm is buyin g 228 00 m 3 of water a year from the GVRD regional water supply, and most of it is u sed for irrigation. The breakdown of UBC Farm’s seasonal water consumption is included in figure 2.1    Figure 2.1: Seasonal Water Consumption for UBC Farm. Adapted from UBC Farm water meter data            3   UBC Farm is paying $0. 6 6 per m 3 in the off peak seasons (spring and fall) and pays $0.8 8 per m 3 d uring peak season. Figure 2.2 (included below) demonstrates the water expenditure per season.    Figure 2.2: Seasonal Water Expenditures for UBC Farm. Adapted from UBC Farm water meter data   2.3 Current Infrastructure  T here is already some infrastructure in or near UBC Farm that can be repurposed for storm water catchment and filtration. T here is a large detention cistern near Nobel Park. T he cistern is currently not being used but it was originally intended  to be used to store up to 1.2 years of storm water overflow. Plant Ops has discontinued using it, but they are potentially allowing it to be used for storm water detainment. Some surveying of the land has already been completed and it has been determined that there is already a semi - wetland in place [CS - 2] , shown in figure 2.3. T his could potentially be expanded into a full retention pool, wetland, or wet po nd.  4    Figure 2.3: Topographical map of UBC Farm including wetland areas Retrieved from “Farm Drainage Map” by Thurber                      5   3.0 CASE STUDY OF AN UNDERGROUND DETAINMENT AND FILTRATION SYSTEM  One optio n for storing rainwater is to use underground storage tanks. Recognizing that open air systems are not always feasible because of a lack of available land, researchers at the University of Edinb urgh built an undergrou nd storm water detention system and assessed its performance (Scholt z & Yazdi, 20 0 9). An example of an un dergroun d storage tank is shown in figure 3.1. In order to assess this type of system for use with the UB C Farm this section will firstly give a description of this system and results obtained by the study and then analyze this system in terms of its environmental, societal, and economic impacts.    Figure 3.1 Example of an underground storage tank Pol ywest(201 3 ). Underground Tank Image. Retrieved from http://www.p ol ywest.ca/zcl - storm water -retention - tanks/   3.1 Methodology and Results           In the stud y, Treatment of Road Ru nof f by a Combined Storm Water Treatment, Detention and Infiltration S ystem, auth ors Scholt z and Yazdi  collected and treated water from a 640 m 2  area consisting of a parking lot and part of a roun dabout , where the entire area is covered with asphalt (20 09, p.56). Water collected in this area then passed throug h a filter. T he filter is of a three layer desi gn and where the top layer is a coarse gravel, the middle layer is finer gravel, and the bott om layer is a mixt ure of sand, 6   EcoSoil© and woo dchips (Scholt z & Yazdi, 20 09, p.57). Once the water has passed through the filter it enters the underground detenti on tank . T he tank used is produced by Alderburgh Limited and has a total volume of 14. 94 m 3  (Scholt z & Yazdi, 20 09, p. 57).            T he study assessed many factors such as flow rates and precipitation data, however these data do not apply directly to how  this system would be applied for the UBC Farm. W hat the study did discuss what the abilit y of this system to filter out pollutants. The study found promising “pollutant removal efficiencies for biological oxygen demand (77 %), suspended solids (83 %), nitro gen - nitrogen (32%) and ortho -phosphate - phosphorus (47%)” (Scholtz & Yazdi, 2009, P.55). Another interesting result of the study was that “50% of the rainfall volume escaped the system as evaporation” (Scholt z & Yazdi, 20 09, P.55).   3.2 Environmental Assessment           An underground system like the one described by the above study wo uld have very little negative impact on the environment. Because it is undergroun d this system can make use of land which is already being used for other purposes. Large areas  for water collection also exist in the form of parking lots and roadways. T here is also the possibilit y of being able to repurpose existing infrastructure, eliminating the need to manufacture new tanks.            W hat this system is missing is the ability  to add much value to the immediate environment. W hile plants can be incorporated into the filter structure (Scholtz & Yazdi, 2009, p.5 7) this system lack some of the other tangential benefits of open air detention systems. Because this system is undergrou n d it cannot provide any habitat for plants or wildlife.   3.3 Societal Assessment           A system such as this would require the consent of the communit y members living in the Westbrook Village area. W hile a system such as this has the abilit y to reuse some existing infrastructure, it would require a fair amount of roadwork to install the filters and upgrade any existing storm water tanks or even install new tanks if needed. T his would be a temporary inconvenience, however during this time it may be a de terment to the qualit y of life for those living near any such works.   Anot her aspect to be considered for the surroun ding communit y would be possible restrictions on what types of fertilizers and pesticides they are using on their 7   lawns. T he filters for th e undergroun d system may not be able to handle large amounts of contaminants. T he communit y may see this as an unreasonable restriction if they value their own lawns and gardens over the wants of the UBC Farm.  The undergroun d system is, for the most part, not visible. W here a filter pond could become an attraction and add to the local scenery, in turn providing a nice place for the communit y to visit and relax, the undergroun d system would become another part of the regular infrastructure which, unless it i s not working, the public has almost no interaction.   3.4 Economic Assessment           Any prop osed system is going to cost money to install and maintain. T his system has the advantage of being able to possibly utilize existing infrastructure. Ho wever, th ere are no existing agreements with the UBC municipalit y to allow the use of any existing cisterns or tanks. Even with such an agreement there will be costs associated with building filter mechanisms, redirecting the current flow of storm water, and mainta ining the tanks. A worst case scenario wo uld mean that UBC Farm would have to install new detainment tanks as well as build the filters.   T hese costs have to be weighed against the cost of using city water. If there is a cost savings per liter of water col lected versus buying water from the city of Vancouver, then it needs to be determined how long it would take to realize those savings versus the costs of building this system.   T here may be tangential economic benefits for the UBC Farm in terms of publici t y and furthering research. T here may be some economic benefits in providing a proof of concept for areas where land resources are limited, such as in cities. T he underground system may, however, be at a disadvantage to above grou nd wet pon d systems. T he u ndergroun d system is not nearly as visible and lacks the natural beaut y of the wet pond systems. W hile the undergroun d system is functional, it is out of sight and out of mind.   3.5 Summary           An underground system has the potential to be a useable system for the UB C Farm if the farm is able to secure access to existing infrastructure. An undergroun d system would be a functional and utilitarian solution for the collection of storm  water.      8    4.0 POTENTIAL WETLANDS FOR UBC FARM  4.1 Overview and Principles of Operation  Wet ponds are a way to implement waste water filtration. T hey have a large pool which can be filled with storm water . There are three main types: detention pond, which is regularly dry, and fills only when there is a storm; a wet p o nd, which has water in it all the time and finally a wet land, which is a wet pond with plant life encouraged to grow in it. T hey detain storm water  runof f in the pon d, works as both catchment and filtration. T hey primarily remove contaminants from storm water  by allowing any sediment to settle to the bott om of the pond, but they also have algae which can help remove some bacteria. If plant life is included in the wet pon d it can also help with filtering the runof f . Containment can be simply having the sto rm water  in the pon d, or the pon d runof f can be moved into a cistern.   Wet ponds are also effective at reducing peak storm water  runof f . T his is because wet po nds have a large amount of extra storage, so any extra rainfall just fills the pon d up higher. Re ducing peak flow is important because too much flow at one time can cause flooding, which can potentially damage the crops and infrastructure at the UBC Farm.   4.2 Design Requirements  Wet ponds require a significant amount of clear land. As they act as a pooling area for rainwater, they also need to be on a low area, where rain water would collect. They need to have a slope which is about 15 percent. They don’t need to have a steep slope, but they do need significant elevation difference between the top an d bot t om of the pool. Improperly designed wet pon ds can also become infested with mosquitoes, so this must be taken into account when designing the wet po nd. For a pon d which is 2000 m3 t he pond must be about 18 m in radius for a depth of 2 m. T his seemed to be the best size for a potential wet po nd because it is a fair balance between dept h and surface area.   4.3 Effectiveness of Wet Ponds as a Filtration and Catchment Technique  9   Wet Ponds are effective for both storm water  catchment and filtration. Wet po nds are effective at controlling the volume and velocit y of the run off . T hey control the velocity of the run off by detaining the water in the holding pools. T his leads to reducing the erosion in local creek beds and streams. They also regulate the volume tric flow rate to the storm water which helps reduce local floo ding.   Wet ponds are also effective at removing pollutants from storm water  runof f . A study by Saunders (19 97) claims they are goo d at removing suspended solids, phosphorus and bacteria (see fi gure 4.1). T he suspended solids will settle to the bott om of the pond and algae in the pools will destroy most bacteria. Unfortunately, wet pon ds lack in removing nitrogen and nitrates.    Figure 4.1: Effectiveness of wet ponds as a filtration technique  4.4 Societal, Environmental, and Economic Analysis          T he use of wet ponds as a storm water  catchment and filtration technique will mostly have a positive effect on the local community and UBC Farm’s culture. Wet ponds are visually appealing if properly maintained which means that the local communit y will probably allow it to be constructed. It also will be a spot that people would want to see, which would attract people to the farm .It also fits into UBC Farm’s goal of becoming less reliant on the GVRD’s water supply. A potential downside of having a wet po nd as a catchment and filtration techni que is that they attract mosquitoes. T his can easily be prevented during construction by ensuring that the water doesn’t stagnate in the pond and that it’s constantly moving.  1 0   Wet ponds will also mostly benefit the environment near UBC Farm. They don’t use  any chemicals during filtration, in fact they remove chemicals from the runof f before the water re - enters the water cycle. They also time average the volumetric flow of the storm runof f , which helps reduce floo ding and erosion. T hey also act as a habitat for local wildlife. T he environmental costs of wet ponds are that they require a lot of land, which would displace local foliage.   Wet ponds can also have economic benefits. UBC Farm spends approximately $180 00 per year purchasing water from the GVRD. A st ud y by Brown claims a 2000 m 3  pond would cost approximately $2 000 0 to construct (including piping and electric pumps to pump into the detention cistern located at Nobel Park) and about 3 - 5% (approximately $50 0) of the initial cost in maintenance; this is c ompared to the $1800 UBC Farm currently pays for 2000 m 3 . T he payback period of the wet pon d is approximately 15 years, but the lifespan of wet pon ds are very long, typically greater than 25 years, so UBC Farm will be saving approximately $12, 0 00 over the life of the wet pon d, demonstrated in figure 4.2.   Figure 4.2: Water expenditure projections for UBC Farm   1 1   4.5 Summary  Wet ponds are one of the recommended best management practices for storm water  catchment and filtration. T hey are environmentally friendly, and have societal benefits. T hey capture and detain storm water in a pond, and then remove most sediment, phosphorus and bacteria. A filtration technique that helps remove nitrates could be adde d before or after the wet pond. Economically, wet pon ds could potentially save the farm $12,0 00 over the lifespan of the farm.     1 2   5.0 CASE STUDY: METHOD FOR WATER CATCHMENT USING ROOF AREA  In this case study, we present an option t hat the UBC Farm could i mplement with readily available materials in order to catch and store rainwater for use during the dry months of summer. This system assumes that there is enoug h roof area to implement the system. A stud y by the University of Arizona shows how one can harv est rainwater using this system (University of Arizona, 199 8 ).   5.1 Methodology and Results  The water catchment system has three components: the source of water, the consumer, and the component that moves the water to the consumer (University of Arizona, 199 8 ).  In our case, the source is rainwater. Depending on the area in which we are capturing rainwater, we can either immediately capture the latter if the surface is impermeable. However, if the surface is permeable, then we will have to wait for it to sa turate with water, then after that, we will start getting runo ff water (University of Arizona, 199 8 ). In the case of the UBC farm (and the study), we are using roof area which has a surface that is impermeable to water th us allo wing immediate catchment. Fi gure 5.3 shows a roof area at the UBC Farm that can be used for implementing the system.   There are quite a number of catchment systems that can be implemented, and they range from simple designs to very complex ones. A simple design can be something that simply redirects the water from the runo ff water of the roof directly to the plants. Figure 5.1 illustrates such a system.   Figure 5.1 ± A simple system to redirect runoff water to plants. University of Arizona (199 8 ) . Harvesting Rainwater for Landscape U se. [online] Retrieved from:  h tt p://ag.arizona.edu/pu bs/water/az1052 /harvest.html [Accessed: 4 Apr 2013 ].   A more complex system would use the same technique discussed above, however, instead of simply redirecting water straight to the plants, it uses a system to catch the water, filter it from any pollutants and particles, move it to a storage tank or cistern,  then when needed, transport it to the plants for watering usin g any technique necessary. The study assumed a drip 1 3   irrigation distribution system. Figure 5.2 shows how such a method can be implemented. Figures 5.3 , 5.4 , and 5.5 show the buildin gs at the UB C Farm that can be used for implementing the system.   Figure 5.2 ± A complex system to catch, treat, store, and distribute rainwater. Uni versity of Arizona (199 8 ) . Harvesting Rainwater for Landscape Use. [online] Retrieved from:  h tt p://ag.arizona.edu/pu bs/water/az1052 /harvest.html [Accessed: 4 Apr 2013 ].    Figure 5.3 ± Harvest Hut at the UBC Farm. Approximate roof area is 100m2  1 4    Figure 5.4 ± Farm Center at the UBC Farm. Approximate roof area is 216m2  Components of complex syst ems that utilize storage include catchment areas, usually a roof, conveyance systems, storage, and distribution systems, to control where the water goes. The amount of water or "yield" that the catchment area will provide depends on the size of the catchme nt area and its surface texture. Concrete, asphalt, or brick paving and smooth - surfaced roofing materials provide high yields (University of Arizona, 1998 ). Bare soil surfaces provide harvests of medium yield, with compacted clayey soils yielding the most (University of Arizona, 1998 ).   A system to move the water from the roof to the next stage would depend mainly on gu tters and drainpipes. For a high capacity, the latter must be sized appropriately. The Farm Center building at the UBC Farm already has a gu tter and drainpipe system in place as can be seen in figure 5.5 .  1 5     Figure 5.5 ± Farm Center at the UBC Farm. A view of the gutters and drainpipes  After being collected from the roofs, the water has to be filtered from debris and any particles that could clog the system in the long run. The first stage of filtration wo uld have to get rid of any leaves and debris that reside on the roofs using gu tter guards. After that, we can choose a number of different filters depending on ho w fine of filtration we would  like. Since this system is aimed towards drip irrigation, a relatively fine filter is required. Since the study did no t discuss any filtration systems, we suggest using drip irrigation filters by Flotender. These filters are optimized for drip irrigation,  and also come with pressurizing pumps for moving water. Figure 5.6 shows one of the filters offered by FlotenderTM.    Figure 5.6 ± A FlotenderTM Grey Water Machine  1 6   The final stage is to store the water in an appropriately sized cistern or tank. There ar e many ways we could go abou t implementing a cistern, and the available options would be to have an undergroun d system, or one above the ground . An o ther thing we must consider is that the tank or cistern must be very well sealed so as to prevent mosquitos and algae growth . Figure 5.7 shows a few commercial cisterns that can be purchased.   Figure 5.7 ± A sample of cistern manufactured by BarrTM Plastics  Instead of purchasing the cistern, we can also build our own in - h o use provided we get the right material s. Figure 5.8 shows such a cistern.    Figure 5.8 ± A cistern that can be built in-house. Courtesy of The Gulf Islands Rainwater Connection Ltd  For the study conducted by the University of Arizona, their results were pretty promising. It was fou n d that fo r a total roof area of 100 0 square feet (Ap proximately 92m2), they were able to harvest a total of 60 5 7 gallons which translates to approximately 25m3 (University of Arizona, 1998 ). The average rainfall for the year in which the study was conducted was 27 centimeters.   1 7   5.2 Environmental Assessment  The system described in this section uses almost all available infrastructures for implementation. This means that the environmental impact is miniscule. The only area of concern for the UBC Farm would be the cis terns itself. Since the latter can cover quite a bit of area, one can argue that it is holding space that can otherwise be used to grow plants thus having a bit of a negative impact on the environment.   5.3 Societal Assessment  Implementing this system is a very small scale project because all the construction work that has to be done will be confined and limited to the groun ds of the UBC Farm alone. The only impact such construction can have is a slight inconvenience for UBC Farm employees since the projec t will inv olve a slight number of modification to the buildings ,which is necessary, especially the main building at the farm which hosts the main offices for the employees. Ano ther inconvenience will arise when in the stage of installing the piping for th e system and connecting it to the main drip irrigation system at the UBC Farm. This will require a temporary shutdo wn of the irrigation system in order to install the full system.   5.4 Economic Assessment  A system like the one proposed in this section has  the potential to save the UBC Farm some money during the dry months of the year.   Following is a calculation to estimate how much water can be caught using the roofs at the farm:   Vancouver has an average annual precipitation of 15 8 8mm. We have a total ro of area of 360m2. So the total water saved per year would be:   Total Water = 1588 mm x 360m2 = 5716 80 litres/year.   So as can be seen from the above calculation the total water saving per year that can be achieved is about 571 00 0 litres, which is equivalen t to 57 1m3.   Other factors we must include are the cost of the system and how much savings will it accumulate over time. Since the system will require a bit of maintenance work, especially when the filters wear out, this also has to be factored in the retu rn on investment. Ho wever, because of the low maintenance nature of this system, one would expect that it will save the farm more over time.    1 8   5.5 Summary  We presented in this section a complete system for capturing rainwater using available roof area at the UBC Farm. This method will allo w us to save on average 571m3 of water annually. This system has a good feature which is its lo w maintenance which translates into go od savings in water cost over time. This system also relies on existing infrastructure a t the UBC Farm which cuts down the costs of development quite considerably.                                       1 9   6.0 CONCLUSION AND RECOMMENDATION  There is a large detention cistern near Noble Park which could be used to store water in order to increase water storage capacity. There is a semi - wet land which already exists at the UBC Farm at location “Site B” shown in section two of the report which can be expanded and made into a full retention po n d .    The first case study at the University of E dinb urgh m ade use of a parking lot which was asphalt surface and sloped it such that all the water is directed towards the cistern undergroun d . This method made use of a three stage filter and was able to filter out pollutants very well. Since this system is undergr ound it is not able to provide a habitat for plants or wildlife. A system such as this one requires a large amount of asphalt to collect water on a large scale which is not available at the UBC Farm since most of the farm has unpaved roads or parking lots.    The undergroun d system is mostly not visible and the public has almost no interaction with it. Ho wever, a wet pon d could become an attraction and add to the local scenery. A wet land works as both catchment and filtratio n naturally. It lets any sediment s settle to the bottom of the pond and to increase storage capacity the water can be moved into a cistern. This method has a lower maintenance cost when compared to other case studies and    The last case study analyzed made use of the roof to catch water. This system is a relatively easy to install since the parts are readily available. Making use of the two large roofs on the farm, the harvest hut and the farm center buildings this system can produce 5716 8 0 liters per year of water. This system is difficul t to scale up at the farm since there is no one single large roof area and the buildings are spread apart. Moreover, this system uses a filtration system and it will require more maintenance when compared to the wet pond system. Also, with any catchment an d filtration system, a pump will be required to move water to desired locations after it is captured.    Therefore, the wet pon d system is the recommended solution for the UBC Farm. Not only will this storm water catchment filtration system make use of rain  water, it will also prevent soil erosion and decrease the load on city of Vancouver’s filtration system. In addition, it will add natural beauty at the farm if designed correctly.   If a wet pon d of 200 0 m3  capacity is made, it will require nearly $20 ,0 0 0  as an upfron t investment for materials such as piping and pumps, etc. Then the maintenance cost of this system would be approximately $50 0 per year. UBC currently spends about $1 ,80 0 for 200 0 m3  capacity of water. Also, wet pon ds are long lived, so based on a 25 years lifetime the UBC Farm saves nearly $12 ,0 0 0 over the lifetime of this system. In order to have a backup storage system, the detention cistern at Noble park can also be used which is 165 0 m3  to make this system more reliable. Therefore, we recommend the wet pon d op tion since it is the most feasible based on the calculations and triple bottom line analysis performed.     2 0   REFERENCES  Alex, P. (2 0 March 201 3 ). Telephone Call.   Brown , W ., and T. Schueler. (19 9 7 ). The Economics of Storm water BMPs in the Mid-Atlantic Region . Prepared for the Chesapeake Research Consortium, Edgewater, MD, by the Center for Watershed Protection, Ellicott City , MD.   Jenny, L. (1 April 2013). Telepho ne Call and Email Message.   Kate, M. (19 March 2013). Interview.   Paderewski, Aleks. (2011). Storm water  for Irrigation Student Project Idea Exploration   Polywest(2 01 3). Undergrou nd Tank Image. Retrieved from http://www. polywest.ca/zcl -storm water - retention - tanks/  [Accessed: 4 Apr 2013 ] .   Scholt z,  Miklas, Kazemi Yazdi, Sara(2009). Treatment of road runof f by a combined storm water treatment, detention and infiltration system. Water, Air and Soil Pollution , 198, 55 - 64. doi:10. 100 7/s11 270 - 008 - 9 825 - 6   Saunders, G. and M. Gilroy. (1 9 9 7 ). Treatment of Nonpoint Source Pollution With Wetland/Aquatic Ecosystem Best Management Practices. Texas Water Development Board, Lo wer Colorado River Auth ority , Austin, TX.    T hurber. (1993). Farm Drainage Map   University of Arizo na (1998). Harvesting Rainwater for Land scape Use. [online] Retrieved from:  ht t p://ag.arizona.edu/pu bs/water/az10 52/ harvest.html [Accessed: 4 Apr 201 3] .              2 1   APPENDIX A   UBC Farm Irrigation Meter Statistics    UBC Farm Water Meter Locations    

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.18861.1-0108488/manifest

Comment

Related Items