Sustainable Water Practices at Pomona's Parks: Improving Irrigation Use and Stormwater Runoff Retention

Transcription

1 Sustainable Water Practices at Pomona's Parks: Improving Irrigation Use and Stormwater Runoff Retention Brandon Bergman California State Polytechnic University, Pomona GEO 435 Dr. Young Winter 2013

2 Abstract The need for water sustainability has emerged as a response to urbanization and the depletion of water sources. Urban green spaces, such as the city parks of Pomona, are at the forefront for the need for sustainable water management. Parks reflect a society's values and ideals, so these green spaces should be leading the way towards a sustainable future. However, this is not the case. Landscape irrigation represents a large portion of the United States total water usage. Further, the majority of stormwater runoff is never recaptured to be utilized in irrigating landscapes. Parks are often inefficient in water use and utilizing stormwater runoff, such as the two parks of this study: Kellogg Park and John F. Kennedy Park. Green infrastructure, Low Impact Development, and Xeriscaping are several practices to improve water sustainability. Sustainable water methods should be implemented to improve stormwater retention and irrigation use at parks. This would prevent the problems created by traditional runoff and landscape design. Although there are many obstacles to implementing these features, especially at the Pomona parks, it is a necessary step towards a more sustainable future. 1

3 Water Problems and Urban Parks The human body is made of approximately 60% water, and without it life as we know it would cease to exist. Water is arguably one of our most critical natural resources, yet our nation's current water use and consumption reveals a disturbing trend toward an unsustainable future. Water is considered a renewable resource, however, it falls short of the abundant use of other renewable resources such as wind and solar energy (Alley, et al.) It is a unique natural resource because of its specific source locations and recharge rates that depend on the natural processes of the hydrologic cycle. Unsustainable water use is a problem when certain regions, like the Southwest United States, have an increasing disparity between population growth and water sources. In California, one of the natural resources that s future is most in jeopardy is water. The depletion of aquifers, reservoirs, and rivers that supply our urban centers with water is a major issue. A common response to urban communities that experience droughts is for the cities to mandate water restrictions (Fam, et al.), such as Los Angeles where local governments have placed restrictions on water use and promoted water conservation. While this may decrease the overall water usage for a period of time, it fails to address the sustainability of the resource as a whole, which is the real issue. The United States Geological Survey has estimated that of the 26 billion gallons of water consumed daily, nearly 8 billion gallons of water is used for outdoor uses, with the majority of that deriving from landscape irrigation use (Water-Efficient Landscaping). Furthermore, approximately ten trillion gallons of stormwater runoff goes unused and untreated (Garrison, et al.). The main cause of this is the impervious surfaces that are found in urban cities, where stormwater is not being captured and utilized. This is a loss of potential usable water which exacerbates our water supply. With nearly 30% of our total water use being directed to 2

4 landscapes, such as urban green spaces, and stormwater runoff not being utilized as irrigation for these locations, it is critical to retrofit existing systems and implement new methods to improve water efficiency and stormwater runoff retention. In recent years, there has been a shift in water resource management to develop new methods to meet the demands of growing populations and to also incorporate ecological values in water policies. Water suppliers and planning agencies are exploring water efficiency methods to improve water use. Jeff Kightlinger of the Metropolitan Water District of Southern California stated that changes must be made and the current system is unsustainable (Kahn). Many cities and counties have responded to this by implementing water principles for better resourceefficient land use as a result of major challenges with water contamination, stormwater runoff, flood damage liability, and concerns for enough reliable water for current residents ("Ahwahnee Principles"). Methods for sustainable water management are not universally accepted yet and are often met by fierce opposition (Gleick). However, recent cast studies have shown that sustainable water practices can be retrofitted to an existing development, are economically feasible, and can be applied at a small-scale (Reducing Stormwater Costs), making an urban park an excellent choice for new implementation features. The Wave of the Future: Sustainable Water Practices Sustainable water practices have flexible definitions and are not universally applicable. The three most prominent sustainable water management practices include the concepts of green infrastructure, xeriscaping, and Low Impact Development ("Low Impact Development"). All of these alternatives are a response to urbanization and the negative effects of impervious surfaces (Dietz). LID is a development plan that works with the natural cycles to manage stormwater. It 3

5 attempts to preserve and recreate natural landscape features and use specific site drainage techniques such as bioretention facilities, rain gardens, vegetated rooftops, rain barrels, and permeable pavements ("Low Impact Development"). Green infrastructure is very similar to LID because it relies on the environment and natural processes to manage the water systems. It also has similar methods such as rainwater harvesting, rain gardens, bioswales, and permeable surfaces. Xeriscaping refers to a landscaping technique that conserves water and protects the environment. It follows several principles such as native and low-water-use plants, limited turf areas, efficient irrigation systems, and use of mulches on the landscape (Water-Efficient Landscaping). This type of landscaping fits very well with the natural landscape of the bioregion which hosts chaparral that are known to be low water use and drought-resistant plants ("Search for Plants"). "If sustainable development is to mean anything, such development must be based on an appropriate understanding of the environment- an environment where knowledge of water resources is basic to virtually all endeavors" - Report on Water Resources Assessment, WMO/UNESCO, 1991(Alley, et al.) There are many benefits to using these green alternatives when irrigating a landscape and managing stormwater runoff. Parks develop connections with adjacent natural areas which benefit many native species that rely on these green spaces to thrive (Morrison). Water-efficient landscaping reduces water bills, reduces landscape labor and infrastructure costs, and decreases the total energy used (Water-Efficient Landscaping). Environmental benefits include a reduction in pollutants caused by stormwater runoff, increased stormwater runoff retention, reduced green house gas emissions, and preservation of the natural environment and native species (Roon; "Reduce Water Usage"). 4

6 Many case studies on sustainable water practices have been completed to see its effectiveness and applicable, especially to urban green spaces. The most common park design features at 11 sustainable water management case study sites in California, the majority being in the Greater Los Angeles region, were: rain garden, green roof, bioretention facility, bioswale, cistern, planting vegetation for soil stability, porous pavers, and porous concrete ("Stormwater Case Studies"). By using recent case studies, guidelines for sustainable water practices, information from the local government, and literature related to water use, I will explore the relationship between the city parks of Pomona and sustainable water practices. Two urban parks were chosen for my case study. Each park's landscape will be examined for sustainable water practices, specific problems created by improper water runoff and landscape design, and the response by the local government to improve the stormwater runoff retention and irrigation use of the city's parks. Case Study Sites Kellogg Park and John F. Kennedy Park were used as case study sites to investigate sustainable water practices at an urban green space. Both parks are within an urban setting located in the City of Pomona. They share a similar water runoff location, the Thompson Creek, which is a concrete channel adjacent to each park. Both parks are located near a school, major freeway, and residential areas (Fig. 1). However, they differ in size and purpose. Kellogg Park is a small park of approximately 2.5 acres. It features a restroom, playground, and open grass areas with interconnecting paved walkways (Fig. 2). The landscape is irrigated and there are three drainage sites for stormwater control. John F. Kennedy is a medium sized park in Pomona with approximately 8.5 acres. It features a community center, baseball field, basketball court, large parking lot, and paved 5

7 walkways (Fig. 3). There is a large undeveloped dirt lot in the southeast corner. The landscape is irrigated and there are three specific drainage sites for stormwater control. The other main drainage location for stormwater runoff is the concrete wash located to south of the park. Figure 1. Case study site locations. Figure 2. Kellogg Park. 6

8 Methodology Figure 3. John F. Kennedy Park. There are many different ways to incorporate sustainable water practices into an urban green space. Several different methods have been used by government and professional agencies which include the concepts of green infrastructure, xeriscaping, and LID. Each of these methods had similar applications, especially when utilized in urban green spaces. Seven criteria from these sustainable water practices were chosen for the two case study sites (Kellogg Park and John F. Kennedy Park). The seven criteria were: natural landscape features which include native vegetation, recycled or reclaimed water use, any type of water-efficient irrigation system, bioretention, bioswales, any type of permeable surface, rain barrels, and the application of mulch on the landscape. These were selected because they are the most prominent solutions to improving irrigation and stormwater runoff, and would have the most pertinent use at an urban green space, according to other case studies completed at parks ("Stormwater Case Studies"). To determine if the two case study sites had any of these methods, the entire park area was examined and the City of Pomona was contacted to discover if there were any plans to implement future sustainable water practices. To establish the current land use of the two study areas, an area calculator tool was utilized to determine the extent of four categories: vegetation coverage which includes turf grass, 7

9 shrubs, and trees; impervious surfaces such as pavement; dirt or undeveloped land; and structures which includes playgrounds, bathrooms, gazebos, and community centers. Kellogg Park was applicable to three of the categories, but not the dirt or undeveloped land category. John F. Kennedy park was applicable to all four categories. These categories were defined in broad and all-encompassing classes to make it easier to manage the data and to create graphs that were easy to follow for the reader. By using Google satellite imagery and an area calculator tool, the land use categories could be quantified by creating polygons which revealed the area in acres. A polygon was created for each study area's perimeter to determine the size of the park. Polygons were then created for each category by outlining the extent of the area of interest from the satellite imagery. By dividing the total acreage of a category by the total acreage of the park, the park's current land use could be shown in percentages. A pie graph was created to illustrate this (Fig. 9, Fig. 10). An adjacent pie graph was created for each park to show the improved land use if sustainable water practices were used (Fig. 9, Fig. 10). The tree and shrub species' nativity and invasiveness are important factors to examine to determine if a park has incorporated natural landscape features, such as native vegetation. Ground truthing, a technique of gathering data in the field to verify satellite imagery data, was used to create a map of each park. Each species was separated into a tree number category and then its location was marked on the satellite imagery to create a map. A photograph was taken of each species to aid in identification. By using a tree inventory list from the City of Pomona (Evans), each tree or shrub specie was determined, which was then verified by a landscape architect. Alternative species were suggested for each tree or shrub species found in the two parks and had to meet the two criteria: native to California and low to moderate water consumption. The suggested alternative species were given by the California Native Plant Link 8

10 Exchange ("Search for Plants"). A table was created for each study area to include the tree number, common name, botanical name, status of invasiveness and nativity, and suggested alternative species (Table 2, Table 3). Problems can arise from not following sustainable water practices. These include stagnant water, damaged pavement, and soil erosion. These issues can be related back to improper surface water runoff and landscape design. To determine if a park had improper proper surface water runoff, each park was visited within 24 hours after a rainstorm. This was done twice. Kellogg Park and John F. Kennedy Park had evidence of all three problems, although at varying levels of seriousness. Results Both urban parks revealed poor results when utilizing or implementing sustainable water practices. Out of the seven criteria discussed early, Kellogg Park had one sustainable water practice and John F. Kennedy Park had none (Table 1). Sustainable Water Practices Kellogg Park Kennedy Park Natural Landscape Features (Native Vegetation) X X Recycled or Reclaimed Water X X Water-Efficient Irrigation System * * Bioretention or Rain Garden X X Bioswales or Vegetated Swales X X Permeable Surfaces X X Rain Barrels or Cisterns X X Mulch X * - City of Pomona is currently doing research to implement this practice. Table 1. Sustainable water practices at both case study sites. 9

11 Not a single park operated by the City of Pomona uses recycled or reclaimed water, which is commonly referred to as "grey water." This is largely due to funding issues because infrastructure and piping would need to be developed for each park. Also, reclaimed water is not recommended for small parks because the cost of infrastructure required to irrigate a small amount of landscape would not outweigh the cost savings (Evans). However, California State Polytechnic University of Pomona and the Frank G. Bonelli Regional Park do use reclaimed water (County Sanitation Districts), but are not within the scope of this research project. Further, bioretention and bioswales were not found in either park. These features are slowly being implemented by city planners across the country though ("Stormwater Case Studies"). Also, both parks did not have any permeable surfaces, but instead used pavement for walkways and parking lots. There was no evidence of rain barrels that could be used to recapture rainwater. Lastly, neither park had a single native species or any other feature of a natural landscape to the bioregion (Fig. 4, Fig. 5). Many of the park's tree and shrub's species are invasive or potentially invasive (Table 2, Table 3). 10

12 Figure 4. Kellogg Park tree and shrub species map. Tree Number Common Name Botanical Name Nativity and Invasiveness Alternative Species¹ 1 London Plane Platanus Acerifolia Non-native; not invasive California Sycamore 2 Deodar Cedrus Deodara Non-native; potentially invasive Pacific Madrona 3 Fern Pine Podocarpus Gracilior Non-native; not Chaparral Oak invasive 4 Paperbark Melaleuca Quinquenervia Non-native; invasive Catalina Ironwood 5 Mexican Fan Palm Washingtonia Robusta Non-native; invasive Blue Hesper Palm 6 Camphor Cinnamomum Camphora Non-native; invasive Blue Oak ¹ - Alternative species are Californian native and have low to moderate water consumption Table 2. The tree and shrub species located at Kellogg Park. 11

13 Figure 5. John F. Kennedy tree and shrub species map. Tree Number Common Name Botanical Name Nativity and Invasiveness Alternative Species¹ 1 Jacaranda Jacaranda Mimosifolia Non-native; not invasive Honey Mesquite 2 London Plane Platanus Acerifolia Non-native; not invasive Hollyleaf Cherry 3 Camphor Cinnamomum Non-native; Chaparral Oak Camphora invasive 4 Cider Gum Eucalyptus Gunnii Non-native; Live Oak potentially invasive 5 Weeping Bottlebrush Callistemon Viminalis Non-native; Buckthorn potentially invasive 6 Desert Gum Eucalyptus Rudis Non-native; Live Oak potentially invasive 7 Brisbane Box Tristania Conferta Non-native; not Manzanita invasive 8 London Plane Platanus Acerifolia Non-native; not Redshanks invasive ¹ - Alternative species are Californian native and have low to moderate water consumption Table 3. The tree and shrub species located at John F. Kennedy Park. 12

14 Kellogg Park's only sustainable water practice was the use of mulch on the landscape. Mulch is a composition of wood chips and grindings, nut shells, and shredded landscape clippings. At Kellogg Park, it was applied to areas of soil erosion and exposed top soil. Mulch has many benefits such as higher water retention rates, soil erosion prevention, and reduction in evaporation rates (Water-Efficient Landscaping). The mulch helps prevent stormwater runoff at the several parts of the Kellogg Park where it was utilized. Kellogg and John F. Kennedy Park will have water-efficient irrigation systems implemented in the future. In 2012, the City of Pomona did research with smart controllers at Washington Park to see the benefits of using a more efficient irrigation system to water the park. During the one-year experiment, the park saw a 40% savings in water use (Evans). Smart controllers are an upgrade component to an existing irrigation system that provides climate controlled features. The controller connects to wireless internet to provide real-time weather information updated provided by the National Oceanic & Atmospheric Administration (NOAA). It can save approximately 20% to 60% more water than traditional sprinkler timers (Evans). By measuring evaporation rates, soil moisture levels, and rain measurements, water will be used more efficiently which will reduce water waste, energy demand, and water-related expenses. The City of Pomona is currently seeking to implement HydroPoint WeatherTRAK Smart Irrigation Controllers or Weather Reach Smart Irrigation Controllers in the immediate future(evans). According to the City of Pomona, developing and implementing a water-efficient irrigation system is the best sustainable water practice that could be utilized. The current park budget for Pomona is approximately 2.5 million, which is a loss of about 300,000 dollars compared to the last year due to budget cuts. The Pomona Park Department main priorities and funding allocations are focused on burglary, vandalism, and tree trimming. However, the city is 13

15 attempting to implement more sustainable water practices, such as the new irrigation system, but it must be funded. Drought-resistant plants and compressed granite walkways are other practices the city would like to implement if they receive a larger park budget (Evans). Not only do the parks lack sustainable water practices, but specific problems are created as a result of not implementing these practices. Both parks had evidence of stagnant water, soil erosion, and damaged impervious surfaces, which are caused by flaws with the runoff and landscape design of the park (Reducing Stormwater Costs; Water-Efficient Landscaping). Both parks had evidence of stagnant water, which was the result of the water not being able to properly drain off of the landscape (Fig. 6). Soil erosion was also discovered, which was evident by sediment draining off the landscape (Fig. 7). John F. Kennedy Park has nearly an acre of undeveloped land which is all dirt, found at the southeast and southern regions of the park. During periods of rainfall, this is a downsloping region has sediment that drains directly into the concrete wash with no buffers to stop it. Lastly, damaged pavement, primarily caused by invasive roots from improper tree placement, was discovered at both parks (Fig. 8). Figure 6. Stagnant water after a recent rainstorm. 14

16 Figure 7. Soil erosion and sediment runoff. Figure 8. Damaged paved walkways. Recommendations for Improving the Parks There are several improvements that could be made at both case study sites as a result of the lack of sustainable water practices and the specific problems it has created. According to the City of Pomona, out of all the different alternative methods, the three that would have the greatest impact and possibility of being implemented are: an efficient irrigation system, permeable surfaces (likely being compressed granite), and planting low water use native plants (Evans). Possible native plants that have low to moderate water consumption and are recommended alternatives for the current park's species can be found on Table 2 and Table 3 ("Search for Plants"). Further, implementing bioswales and bioretention facilities, especially in 15

17 regions with sediment runoff and erosion (such as by the concrete wash at both park locations), would be incredibly beneficial in reducing pollutants and stormwater runoff. By implementing these practices, both park's land use would change, allowing for an increase in the retention of stormwater and more efficient irrigation use. Kellogg park would see a shift from impervious surfaces to permeable surfaces, with no change to the total area of any category (Fig. 9). John F. Kennedy Park would see a shift to a greater amount of vegetation as the dirt regions become developed and the impervious surfaces are replaced with permeable surfaces (Fig. 10). Kellogg Park Current Land Use (2.55 acres) Pavement 16% Kellogg Park Improved Land Use (2.55 acres) Permeable Surfaces 16% Vegetation 80% Structures 4% Vegetation 80% Structures 4% Figure 9. The current and improved land use of Kellogg Park. John F. Kennedy Park Current Land Use (8.62 acres) Dirt 21% Dirt Pavement 21% 24% John F. Kennedy Park Improved Land Use (8.62 acres) Permeable Surfaces 24% Vegetation 51% Structures 4% Vegetation 72% Structure 4% Figure 10. The current and improved land use of John F. Kennedy Park. 16

18 The Grass Isn't Always Greener: Implementation Issues A park attempts to preserve the natural state of an area, yet it is also controlled, shaped, and manipulated to fit our own interpretation of nature. Thus, the concept of urban park restoration, such as returning natural landscape features to the park, is often subjective because of our cultural values. Stakeholders have different visions when restoring the natural of an urban open space, such as restoration to the original habitat or restoration for recreational activities. Restoration can be an ambiguous concept and in urban park landscapes many different natures can exist (Gobster). Choosing the right one is difficult because it must integrate diverse values of both culture and nature. Not every stakeholder will support many of the different applications of sustainable water practices because it does not fit within their values of what a park should be. Parks are also a dynamic concept which leads to many different types and purposes of parks. The size and location of a park plays a critical role in how it will be developed. Some sustainable water practice features, such as permeable surfaces, often conflict with the purpose of a park. John F. Kennedy has a basketball court, an impervious surface, that would be difficult to remove because the community uses it for recreational activities. Many compromises will have to made to strike the right balance between water sustainability and the purpose of the urban park. There are also challenges that need to be addressed with some methods that utilize sustainable water practices. Low Impact Development (LID) practices have had issues with the retention of certain pollutants, such as nitrate and phosphorus (Dietz). Further, attempting to preserve native biological diversity can be challenging. Sometimes removing exotic species can threaten native species or cause the spread of a new exotic species. In some circumstances, exotic species can also aid in the restoration of a landscape (D'Antonio). This reveals the 17

19 difficulty in truly knowing how the restoration of a natural environment will affect a park. Although negative impacts can occur when implementing sustainable water practices, it is still a huge benefit to improving stormwater runoff and irrigation. Lastly, politics and funding always play the most critical role with any new implementation at a park. The City of Pomona park's budget is consistently being reduced and their workforce has been slashed in half in recent years (Evans). Without the ability to dedicate funds, sustainable water practices cannot be implemented. Furthermore, there needs to be a revision of the city's ordinances and regulations to accommodate these changes. Lastly, there needs to be public involvement to provide a backing to the new implementations (Garrison, et al.). Conclusion Parks serves an important role in society as more than just a space for nature and recreation, but a place that embodies society's ideals, traditions, and hopes. Sustainability has emerged as a critical concept to the development or redevelopment of structures and open spaces, such as parks, as water crises become more apparent. Stakeholders, local governments, and professional organizations should concentrate their efforts to implement sustainable water management features and methods. Urban parks, unfortunately, often embody the problems of inefficient irrigation use and stormwater runoff. By implementing sustainable water features at parks, many people could see the benefits from the reduced infrastructure and water costs, reduced energy use, pollutant filtration, and stormwater runoff retention. The path to a more sustainable world may begin at the park down your street. 18

20 References "Ahwahnee Principles for Resource-Efficient and Livable Communities." Local Government Commission. Web. 12 Mar < Alley, William M., Thomas E. Reilly, and O. Lehn. Franke. Sustainability of Ground-water Resources. Denver, CO: U.S. Dept. of the Interior, U.S. Geological Survey, Print. County Sanitation Districts of Los Angeles. Annual Status Report on Recycled Water Use. By Stephen Maguin. 18th ed. Print. D'Antonio, Carla, and Laura A. Meyerson. "Exotic Plant Species as Problems and Solutions in Ecological Restoration: A Synthesis." Restoration Ecology 10.4 (2002): Wiley Online Library. Web. 29 Jan < Dietz, Michael E. "Low Impact Development Practices: A Review of Current Research and Recommendations for Future Directions." Water, Air, and Soil Pollution 4th ser (2007): Springer Link. Web. 29 Jan < Environmental Protection Agency. Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices Print. Environmental Protection Agency. Water-Efficient Landscaping: Preventing Pollution & Using Resources Wisely. Print. Evans, Bill. City of Pomona Parks Department. Personal interview. 28 Feb Fam, Dena, Edward Mosley, Abby Lopes, Lorraine Mathieson, Julian Morison, and Geoff Connellan. Irrigation of Urban Green Spaces: A Review of the Environmental, Social and 19

21 Economic Benefits. Tech. no. 04/08. CRC for Irrigation Futures. Web. 29 Jan < Garrison, Noah, and Karren Hobbs. "Rooftops to Rivers: Green Strategies for Controlling Stormwater and Combined Sewer Overflows." Natural Resources Defense Council (2011): Print. Gleick, Peter H. "A Look at Twenty-first Century Water Resources Development." Water International 25.1 (2000): Print. Gobster, Paul H. "Visions of Nature: Conflict and Compatibility in Urban Park Restoration." Landscape and Urban Planning 2nd ser (2002): Science Direct. Web. 29 Jan < Kahn, Carrie. "Calif. Water In Short Supply, Restrictions In Place." NPR. National Public Radio, 18 May Web. 12 Mar < "Low Impact Development." Environmental Protection Agency. Web. 23 Jan < Morrison, Michael L., Thomas A. Scott, and Tracy Tennant. "Wildlife-Habitat Restoration in an Urban Park in Southern California." Restoration Ecology 2.1 (1994): Wiley Online Library. Web. 29 Jan < "Reduce Water Usage in Landscapes." California. Web. 12 Mar < 20

22 "Search for Plants." California Native Plant Link Exchange. Web. 12 Mar < "Stormwater Case Studies." American Society of Landscape Architects. Web. 23 Jan < Roon, Marjorie. "Water Localisation and Reclamation: Steps towards Low Impact Urban Design and Development." Journal of Environmental Management 83.4 (2007): Print. All photographs taken by Brandon Bergman. 21