STORMWATER Best Management Practices for East Baton Rouge Parish - Master Development Program

City of Baton Rouge - Parish of East Baton Rouge City Parish Planning Commission CPPC EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

STORMWATER Best Management Practices East Baton Rouge Parish - Master Development Program

Made possible in part by grants from the Louisiana Department of Environmental Quality

July 2007

in collaboration with BROWN+DANOS landdesign, inc. MISSION STATEMENT

MISSION STATEMENT

“It is an undisputable fact that most, if not all, land development and public improvement projects have an impact on the natural conditions of adjacent areas. Unfortunately, this impact is negative due to the intrusion of civilization upon any environment. The purpose of the (committee) is to minimize or eliminate these adverse impacts through the promulgation of guidelines, policies and procedures designed to protect the environmental quality of surrounding areas and water bodies, through education of the public; and through utilization of existing environmental systems integrated with urban planning.” City-Parish Wetlands Steering Committee, 2006. EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM CONTENTS

CHAPTER 1 INTRODUCTION 1

Water Bodies and Hydrology 2 Water Pollution Problems 4 Improving Water Quality 5 The Stormwater Treatment Train 5 Using BMPs to Improve Water Quality 6

CHAPTER 2 STORMWATER MANAGEMENT PLANNING PROCESS 9

Step 1: Identify and Analyze Site Conditions 9 Context 9 The Development Site 10 Step 2: Prepare a Preliminary Stormwater Management Plan 12 Runoff Rate and Volume 12 Likely Pollutants and Treatment Objectives 14 Schematic Site Water Quality Impact Study 14 Step 3: Prepare a Final Stormwater Management Plan 15 Water Quality Impact Study 15 Integrating BMPs Into the Planning Process 18 Water Quality Boulevard 19 Water Quality Road 20 Environmentally Sensitive Parking Lot 21 Water Quality Residential Lot 23 Water Quality Commercial Property 23 Benefi ts to Development 24

CHAPTER 3 CONSTRUCTION PHASE 25

Stormwater Pollution Prevention Plan 25 Site Clearing BMPs 26 Erosion Control BMPs 26 Sediment Control BMPs 27 BMPs to Control Water Runoff 27 Good Housekeeping Measures 28

CHAPTER 4 SITE MANAGEMENT AND MAINTENANCE 29

Maintaining the Treatment Train 29 Good Housekeeping Measures 29 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

CHAPTER 5 STORMWATER BMPs 31

Detention and Retention Systems 32 Dry Pond 32 Wet Pond 32 Pond Edge with Bulkhead 33 Pervious Paving with Manufactured Subsurface Storage 34 Infi ltration Systems 35 Pervious Paving 35 Pervious Paving with Aggregate Subsurface Storage 36 Infi ltration Device 37 Cistern 37 Filtration Systems 38 Bioswale 38 Stormwater Planter 1 Permeable 39 Stormwater Planter 2 impermeable 40 Sand Filter Basin 41 Catch Basin Insert 42 Water Quality Wetlands 43 Rain Garden 43 Green Roof 44

CHAPTER 6 RESOURCES FOR STORMWATER BMPs 47

Websites 47 City Parish Contacts 47 Reference Books 48

CHAPTER 7 GLOSSARY OF TERMS 53 CHAPTER I INTRODUCTION

INTRODUCTION necessary to protect the watersheds INTRODUCTION within and around the City of Baton This document summarizes the work Rouge-Parish of East Baton Rouge from that was completed by the Louisiana the adverse impacts of nonpoint source Department of Environmental Quality pollution. (LDEQ), the City-Parish Planning Commission (CPPC), and Louisiana Stormwater management (SWM) is a State University’s School of the Coast diverse issue that concerns practically and Environment, in association with everyone, including engineers, the grant entitled, “Mitigating Nonpoint landscape architects, architects, Source Pollution in Urban Watersheds planners, developers, environmentalists, with Spatial Modeling, Best Management public offi cials, civic groups, realtors, Practices for Wetlands and Community homeowners, and renters. They can Outreach.” all use this information as practical guidance in site planning and design, The sources of water pollution are control of pollutant sources, and characterized as either nonpoint or stormwater treatment. The result will point source pollution. Point source mitigate urban runoff pollution and pollution can be traced to a specifi c spot improve stormwater management as the source, such as pollution from for new development projects or industrial waste or sewage treatment redevelopments of underutilized land. plants. Nonpoint Source (NPS) Pollution originates from many diffused sources The ways in which land is developed that deposit pollutants on the ground. and used is the most obvious and Pollution occurs when rain, snowmelt infl uential contributor to urban runoff. or irrigation drains over (runoff) and There is a direct correlation between through (fi ltration) the ground. As the human activities and regional patterns runoff moves, it picks up and carries of wet and dry pollutants entering the away natural and manmade pollutants, urban landscape. Undeveloped land ultimately depositing them into lakes, in its natural state is very effective in rivers, wetlands, coastal waters, and minimizing stormwater runoff and water even aquifers (underground sources pollution through several processes. A watershed of drinking water). This Master is the specifi c Development Program Manual will The quantity of runoff is minimized land area that guide the implementation of measures compared to developed land because drains water into a river system or other body of water.

Figure 1: Hydrologic Cycle, Natural Environment 1 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

trees, shrubs, grasses and other plants watersheds. Best Management Practices utilize the water, taking it in through (BMPs) can be applied to individual leaves and roots. Plant leaves dissipate developments within these watersheds. the energy of raindrops, which reduces The scale of the new sub-watershed is a impact on the ground and, in turn, compromise between development and reduces erosion. Rainwater and runoff the water quality assessment made by are also slowed by plants, providing regulatory authorities (G. Paul Kemp, more time for evapotranspiration and 2005 Annual Report). infi ltration processes to occur. Finally, water that does become runoff is Using existing Light Detection And fi ltered and treated by plants, resulting Ranging (LIDAR) Data, EBRP was in cleaner water entering lakes and divided into fi ve geologically defi ned streams. terraces that change in elevation from Our water south to north beginning with the bodies must Typical urban development practices in Manchac Alluvium, continuing through be fi shable and Louisiana often begin with completely Terraces 1, 2 and 3, and fi nally to the swimmable. clearing the land, leaving it unprotected. Mississippi River Drainage terrace. Construction activities, particularly Elevation thresholds were derived for earthmoving and grading work, increase each area to separate source (runoff soil erosion, runoff, and water pollution. producer) from sink (runoff receiver) Projects are typically designed and built zones. The sink zones have historically with signifi cantly increased impervious experienced occasional backwater surfaces, such as roofs, roads, and fl ooding (Kemp et al. 2005), and make up parking areas. The result creates higher approximately 18 percent of the Parish peak fl ows which in turn increases (Figure 2). pollutant runoff and pollution deposition into lakes and streams. This typical East Baton Rouge Parish is bordered urbanized condition also contributes on three sides by natural waterways. to backwater fl ooding in Louisiana. The Mississippi River is the western Backwater fl ooding is upstream fl ooding boundary and receives a limited amount caused by downstream conditions such of drainage from the northeastern part as channel restrictions or high fl ow in a of the parish and downtown Baton downstream confl uence of waterways. Rouge. Bayou Manchac, formerly a The water has no place toward which to tributary of the Mississippi River, is the drain, so it backs up and fl oods the areas southern boundary and drains much upstream. of the southern part of the parish. The Amite River fl ows north to south along Water Bodies and Hydrology the eastern boundary and receives all the water from Bayou Manchac and the The LDEQ and the U.S. Environmental Amite River watershed. The northern Protection Agency (EPA) have assessed boundary is drawn along a latitudinal water quality for ten hydrologic sub- line (roughly 30.7o north latitude) and basins in East Baton Rouge Parish is not defi ned by a drainage feature. (EBRP). Louisiana State University’s Within the parish the average rainfall (LSU) School of the Coast and is 77.64 inches per year, which also Environment Research Team divided the signifi cantly contributes to the Baton LDEQ sub-basins into smaller sub- Rouge waterways.

2 INTRODUCTION

According to the 1996 National Water Quality Inventory, stormwater runoff is a Amite River leading source of water pollution.

Mississippi River

Bayou Manchac

Figure 2: Watersheds and Elevation in East Baton Rouge Parish

Table 1: East Baton Rouge Parish Terrace Elevation Thresholds 3 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Water Pollution Problems of each pollutant into each segment, with the purpose of improving water quality. According to the 1996 National Water Quality Inventory, stormwater runoff Pollutants generated by human activities, is a leading source of water pollution. deposited over exterior surfaces, such A Total Maximum Daily Load (TMDL) as rooftops, parking lots, streets, patios, establishes the maximum amount of a lawns and any other open land, are pollutant (sum of allowable pollutant exposed to rain. The pollutants are loads from point and nonpoint sources) washed and carried out by rainwater that can be released into a water body runoff into streams, ponds, lakes, The sources without causing the water body to and ground water. Typical pollutants of water become impaired and/or violate state include excess fertilizer, herbicide, pollution are water quality standards (Source LDEQ). and insecticide from agricultural lands characterized Early efforts in improving water quality and residential areas; oil, grease, and as either focused on regulating discharges from toxic chemicals from urban land uses nonpoint or traditional “point source” facilities; such and energy production; sediment from point source as municipal sewage plants and industrial improperly managed construction sites, pollution. facilities. In many cases it was found that crop, forest lands, and eroding stream only addressing “point sources” did not banks; salt from irrigation practices; adequately reduce pollutants. Additional acid drainage from inactive mines; and measures under Section 303(d) of the bacteria and nutrients from livestock, pet 1972 Clean Water Act require states to wastes, and faulty septic systems. develop a list of water body segments that are impaired or limited in quality. Activities which generate pollutants These water bodies do not meet water include landscape irrigation runoff, quality standards even after point source street washing, car washing, cleaning pollution prevention measures have been of outdoor facilities, groundwater implemented. Federal law requires that seepage, illegal connections, hydrant state and local jurisdictions establish fl ushing, construction runoff, and other priority rankings for water quality limited commercial and residential activities. A Water-based segments on the lists and develop common characteristic of urban runoff activities Total Maximum Daily Loads (TMDLs). is the transport of pollutants into the are a central TMDLs for each segment, as their name stormwater collection system through component implies, set the standard for discharges the gutter of an adjacent road. Any of our culture and daily social lives.

d a b e c f

a deep groundwater (5%) b runoff (55-75%) c interflow (10%) d evaporation/transpiration (15-25%) e fencing f concrete lined drainage canal

Figure 3: Hydrologic Cycle, Typical Manmade Environment 4 INTRODUCTION 5 ooding rst and rst of treatment should of treatment should of the treatment ltered and cleaned ows through the pipe or rst stage fi second stage third stage ows with it, some of which might not The Stormwater Treatment Train Treatment The Stormwater When properly and designed, planned stormwater is fi through BMPs before a series of This reachinga surface water body. is called the stormwater treatment the distance and time train. The longer stormwater must travel before beginning treatment, the more pollutants it collects and carries. Therefore, the fi most effective place to implement BMPs is at the source, that is, whererain the falls. The scale. train is at the site development Stormwater runoff should be reduced at the site and runoff occur that does should be treatedthrough onsite a series of stormwater BMPs. This will require remain the water to onsite for a longer time for treatment to occur before leaving, while being certain that fl The treated stormwater does not occur. either would leave the site by entering the city’s storm system through drainage a subsurface pipe or open waterway. As the water fl waterway, stormwater from other sites fl have been adequately treated. The occur offsite, but within the same subwatershed to further the water clean before it enters the larger watershed along with other waters. Treatment can be accomplished by implementing BMPs along the waterwayand at the lowest area of the subwatershed at the outfall. Manufactured BMPs are available for in-pipe treatment as well. The occur within the larger watershed before the water enters the basin. In the case of East Baton Rouge Parish, the basin is Lake Pontchartrain. the Considering owing shable and swimmable. ll development, ll sh and wildlife that depend upon it for Why is it important to protect our sourcewaters? Nonpoint pollutants are transported by runoff over impervious ground surfaces or through the layers of soil into surface water bodies and subsurface aquifers, contaminating the quality of drinking water and creating a threat waterbodies to public health. For that are not a source of drinking water, protectingwater quality is critical both to humans during recreation activities and fi water sustenance. Simply stated, our bodies must be fi Furthermore, East Baton Rouge Parish in its entirety Bayou Manchac drains into and ultimately and the Amite River, into Lake Pontchartrain. This makes nonpoint source pollution an issue in East Baton Rouge Parish because it affects much of the southeastern section of the state. Although this manual focuses on single developments, a regional perspective is also needed. Stormwater management can be and must be implemented at the regional scale by discouraging urban sprawl, encouraging infi and preserving natural features. Developers are more focused on their individual development projects, but their development practices can be greatly enhanced through regional and statewide measures. This manual focuses on SWM for land development. Improving Water Quality Improving Water pollutants that arepollutants roads associated with and streets and be washed away will also pollutant to the myriad will contribute particular by the loads generated land All surfaces will, therefore, use activity. have a direct impact on runoff water quality with greater impacts occurring from runoff generated by water fl over impervious surfaces. EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

parish is part of such a large water basin, fl ows into the lake. Where wetlands a site’s sub-watershed is nested within do not exist, other stormwater BMPs other larger watersheds, sub-basins, should be implemented, completing the and basins. As in the second stage, stormwater treatment train within the treatment can be accomplished along the Lake Pontchartrain Basin. waterways and at the outfall of each sub- watershed as it empties into the larger Using BMPs to Improve Water Quality watershed. The use of BMPs for Stormwater The fi nal stage of treatment within Management (SWM) offers an the basin should be at the outfall into alternative to the typical practices of Lake Pontchartrain. Wetlands can be conveyance by minimizing impervious found all around the lake in areas that surfaces and mitigating changes to have been developed right up to the the natural hydrologic system. This lake edge. In these areas, the natural is termed “Integrated Stormwater wetlands serve an important function Management,” an approach which in fi ltering and cleaning water that regards stormwater as a resource rather

POLLUTANT LOAD

Stormwater Runoff

local watershed basin creek site channel or creek or or stream or pipe stream lake

does not reduce pollutants and worsens TMDL

Typical Development Approach Development Typical TMDL criteria

reduces pollutants to help Stormwater meet TMDL criteria Runoff BMPs

basin creek local water- watershed site BMPs BMPs BMPs channel or shed basin or stream or creek or BMPs pipe BMPs stream lake

BMPs

Stormwater Management Approach Management Stormwater POLLUTANT LOAD Figure 4: Development Stormwater Treatment Train 6 INTRODUCTION 7 d evaporation/transpiration (30%) evaporation/transpiration d Figure 6: Most Louisiana residents live near a water resource • To use stormwater• To as visual and recreational amenities in the landscape. of • Add value and enhance sense place while minimizing development costs. interflow (45%) c c ows by lter and b runoff (10%) b a cial drainage facilities can deep groundwater (15%) deep groundwater a • To protect the quality of water • To bodies and groundwater by effectively using BMPs to fi protect and enhance natural • To hydrologic systems. reducing impervious surfaces remove pollutants from runoff. • To reduce runoff• To fl and peak Figure 5: Hydrologic Cycle, Green Environment Figure 5: Hydrologic must be disposed. than as waste which recognizesIntegrated SWM all aspects of hydrology and water resources: environmental, cultural. social, and bodies are found throughout Water Louisiana and most residents live near a water resource. a result, As water- based activities are component a central of our cultureactivities. By and social the utilizing a site’s natural hydrology, size of artifi The goals of integrated SWM are be minimized. Conserving and utilizing natural hydrology the natural means less integrity of the site is disturbed and the environmental, and social, cultural resources the site remain of natural intact. Integrated SWM utilizes drainage corridors and areas in multiple ways, serving drainage, water quality, and aesthetic, wildlife, and recreation functions. Multi-functioning streams, lakes, and wetlands mimic how water resources have historically performed in Louisiana. EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

8 CHAPTER 2 STORMWATER MANAGEMENT PLANNING PROCESS STORMWATER MANAGEMENT example, the natural site hydrology PLANNING PROCESS and existing vegetation should be used as the basis for the development’s To effi ciently and effectively manage and drainage scheme, which will also serve treat stormwater onsite, it must start at to maintain water quality. the beginning, at the site planning stage.

This chapter will address SWM in two STORMWATER MANAGEMENT PLANNING PROCESS major steps in the site planning process: Existing Conditions Analysis and Schematic Site Planning. Stormwater management in site design is addressed in Chapter 4.

Step 1: Identify and Analyze Site Conditions

In East Baton Rouge Parish, the typical development approach is to fi rst completely clear the site of vegetation and grade it to fi ll in low areas and Figure 7: Typical Development, no erosion control measures employed create an even surface of soil. This usually results in the loss of rich topsoil Context that could be stockpiled for use later in planted areas. The practice also causes Understanding the surrounding setting the uncovered soil to erode during of the development site is important in rainfall, often fl owing into and polluting planning the SWM and in knowing how creeks, rivers, and subsurface drainage the hydrology, terrain, and vegetation systems. link with other areas. For instance, how close is the development site to For subdivision developments, as the subwatershed outfall or to a creek, many residential lots as possible are stream, or lake? Does the elevated part planned along roadways that access the of the site offer special views of nearby entire property. Massive retention/ landmark buildings or historic areas? detention basins are used to retain the Is a small waterway part of a larger stormwater runoff from the increased network of vegetated waterways that area of impervious surfaces. This typical provide wildlife habitat? The answers to approach creates a small percentage of these types of questions should inform lots with “lake views” which are actually the site planning, and ultimately the views of retention basins that are not design, of the development. designed as lakes. The overriding fl aw in the typical approach is that In analyzing the topography of the site the resulting development has little and surrounding land, it is critical to relationship to the original site and, as identify the location of the site within a result, has little character or identity. its subwatershed. A map of East Baton This represents a missed opportunity Rouge watersheds is available online at to create a distinctive and more easily http://www.brgov.com/dept/planning/ marketable development that utilizes its wetlands.htm. All of the watersheds in cultural and natural resources. As an EBR Parish are sensitive because all 9 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

of the water drains directly into either The Louisiana Department of the Amite River or Bayou Manchac and Environmental Quality (LDEQ) is in the then the Amite River. Both waterbodies process of testing water samples from are identifi ed by the EPA as impaired EBR Parish waterbodies and will provide and not in compliance with the Clean on their website information about Water Act. EBR Parish must meet its pollutant levels, total maximum daily responsibility in substantially reducing loads (TMDLs) allowed, and any water water pollution so that these waterbodies quality restrictions for developing within become compliant, otherwise fi nes and each waterbody’s watershed. All of this development restrictions will likely be information will determine not only the imposed. criteria for designing a development’s drainage system for water conveyance Upstream watersheds contribute and fl ood prevention purposes, but also pollution that affects downstream criteria for improving water quality. waterbodies and are considered source areas for water contaminants. The Development Site Downstream watersheds not only contribute to water pollution, but bear Understanding the development site’s the burden of upstream pollution and are hydrology is important in planning post- considered sink areas that receive the development drainage and stormwater polluted waters. It is even more critical management. Identify the high points to treat stormwater in sink areas because and ridges as well as the low points and they represent the last opportunity swales or channels. In which directions before the water enters Bayou Manchac does the water fl ow in all areas of the and the Amite River. In addition to site? Defi ne the watershed boundaries locating the watershed within which the on the site. It is likely that some site lies, small watersheds will not be wholly the surface waterways and underground contained within the site and will be drainage system, as well as fl oodplains, shared with adjacent properties. The must be identifi ed and researched. The above described analysis of the site’s East Baton Rouge Parish Department context will be helpful here. A simple of Public Works (DPW) can provide diagram of existing watersheds and information on fl oodplains, the low fl ow surface hydrology on the site should be and fl ood stage of surface waterways, prepared. (see fi gure 9) In addition to and the capacity of culverts and analyzing the surface drainage patterns, underground pipes. the pre-development runoff rate and volume for a minimum ten-year design Amite storm should be calculated. River The site’s topography and slope should be analyzed, along with soils, to be aware of potential for soil erosion during both the development’s construction phase and post-occupancy when stormwater Bayou Manchac BMPs are functioning. Steeper slopes, Elevation < 13 ft 17 ft - 40 ft > 53 ft particularly in highly erodable soils, 13 ft - 17 ft 40 ft - 53 ft watersheds should be identifi ed for protection and Figure 8: Closeup of the Southeast East stabilization. Floodplains and areas 10 Portion of Baton Rouge Parish susceptible to fl ooding should be STORMWATER MANAGEMENT PLANNING PROCESS 11 “Did you know that because of impervious surfaces such as pavement and rooftops, a typical city block generates 9 times more runoff than a woodland area of the same size?” website EPA exists sh, if a waterbody wetlands, ponds, and creeks cover the land within the site. Bare soil will erode during rainstorms, while vegetation holds soil together and prevents erosion. or minimizes Mature stands of trees can be maintained and protected rather than cleared, creating amenity and an possible stormwater BMP as well as reducing runoff from the development. Major stands of vegetation onsite might be part of an even larger stand when examined in the site context. This could mean the vegetation provides habitat for wildlife and fi within. Once again, such a resource on site should be conserved and used as an amenity with trails and passive recreation, as well as for stormwater management. Less environmentally valuable portions can be more of the site densely developed to provide for full development rights. and planting media ltration rates In other words,ltration rates. such Vegetation and land cover, such as and land cover, Vegetation grasses, concrete, asphalt, forests, Soil borings from the areas suitable for development should be tested, not just for structural purposes, but for infi Much of EBR Parish has silty quality. clay soils characterized by very low infi soils hold the water for long periods of time before reaching groundwater. Some parts more of the parish have permeable soils. The types of soils and their depths is importantselecting and in design BMPs as described in Chapter 4. mapped and development minimized mapped and development minimized in those areas where possible. Higher areas on the site are the prime development zones. Concentrating leaving development in higher zones and the lowest lying areas conservation as and for stormwater management saves construction costs and long term maintenance post-construction. Figure 9: Step 1, Existing Watersheds and Surface Hydrology Map Figure 9: Step 1, Existing Watersheds EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Development Development Notes regarding the developments statistics preservation of natural areas

Garnet Oaks 80 homes 51% of the land preserved as open space, including woodlands, tree specimens, Bethel Township, 58 acres and structures from the property’s original estate Pennsylvania Housing price premiums are based in part on the lots’ proximity to open space

Newpoint 124 homes The site layout preserved small wetlands and saved many large existing trees, some in the greenway between the street and sidewalk Beaufort, 54 acres South Carolina The riverside green and a community dock provide river access for the neighborhood

Prairie Crossing 337 homes 350 acres devoted to prairies, pastures, farms, fields, gardens, marshes, & lakes Grayslake, 667 acres Community-supported organic garden

Illinios The community is the western anchor of the Liberty Prairie Reserve, a 2,500-acre preserve of forest, marshes, prairies, and farmland 60 percent of the community's land preserved as permanent open space The Fields of 90 homes 226 acres Home sites are clustered near a wooded ridgeoverlooking the site's ponds and St Croix open space Lake Elmo, Minnesota An historic Civil War-era barn was preserved and used as a community center Thirty acres of prairie restoration featuring native plants indigenous to the area

Existing wooded slopes, which are home to many specimen oak trees and provide excellent wildlife habitat, preserved

The open space is permanently guaranteed by a conservation easement granted to the Minnesota Land Trust Table 2: Examples of community design which took site hydrology, topography, and soils into consideration while planning the development and maintained natural site features as amenities

The following table lists just a few of the To guide more sustainable site planning, many subdivision and new community a schematic site WQIS should be projects across the nation that have prepared once the developable areas are employed this approach. It is worth identifi ed. The preliminary WQIS will noting that homes in these developments take into account the rate and volume typically sell quicker and at higher prices of post-construction runoff, the likely than those developed on sites that have pollutants in the stormwater, treatment been completely cleared of its natural objectives, and the site’s stormwater resources. treatment train.

Step 2: Prepare a Preliminary Runoff Rate and Volume (post- Stormwater Management Plan construction)

A Stormwater Management Plan (SMP) In planning the development, it is is composed of two parts, the Water imperative that all increased runoff post- Quality Impact Study (WQIS) and the development remain on site until the Drainage Impact Study (DIS). The DIS city’s stormwater system has capacity to is described in the East Baton Rouge receive it. More importantly, all runoff Parish Unifi ed Development Code from the site after development must be (UDC) and the WQIS is detailed below. treated using stormwater BMPs, so the 12 amount of water to be treated must be STORMWATER MANAGEMENT PLANNING PROCESS 13 t of t The economic benefi using a natural drainage system was demonstrated in The Woodlands community north of Houston, Texas: the construction estimates for the “storm sewers required for the conventional system were $18,679,300, while the natural drainage systems costs were $4,200,400…a savings of $14,478,900.” The Woodlands, 1973 WRT, c,

(cfs) ows per subwatershed per BMP for expected impact to affected waters

• parking on current show plan, indicate site area (acres of SF) • • retail commercial building • outdoor market • auto repair area • building maintenance • trash collection • restaurant grease disposal area • kitchen yard • salvage • restaurant dining area nursery • plant growing area • dry cleaning • chrome plating roadways washing • car station • fueling etc. storage • lumber • • recreation areas park • dog • • Empirically expected pollutants units • dwelling and activities uses, from land cover, subwatersheds Quality Treatment C. Proposed Water drainageways • Stormwater Treatment Train BMPs • • • sizes fl • Water • BMPs function • • • water capacity • Operation and maintenance housekeeping • empirically expected pollutant reduction (percentage) • • control and containment per special activity D. Conclusion of empirically expected • Table percent removal of each pollutant • Land cover comparison table comparison • Land cover -- be specifi uses and activities • Site •existing versus proposed cations cations c, show on a show on a c, • waterbodies www.deq.louisiana.gov/portal/ www.deq.louisiana.gov/portal/ B. Proposed Conditions and subwatersheds • Watershed (on and off site) • route of drainageways to outfall that connects to Bayou Manchac or the Amite River • indicate proposed modifi wetlands etc. • • current photo and in a table aerial forest with land cover area (acres or and percent of total site SF) meadow • crops buildings • waterbodies • wetlands (list by type) • paving • etc. • • • • Land cover -- be specifi to the existing drainage pattern current aerial photo / site plan and forest (map and design cross-sections) in a table with land cover area (acres or SF) and percent of total site meadow • rooftops • • • paving (list by type) A. Existing Conditions A. Existing location • Site and subwatersheds • Watershed (on and off site) • route to the of drainageways Manchac Amite River or Bayou waterbodies Maximum Daily Loads •Total affected (TMDLs) for applicable tabid/130/Default.aspx • Soils and Topography contours at maximum • site contour interval two-foot • Land cover -- be specifi land slopes • general types and characteristics • soil Water Quality Impact Study Outline Impact Water Quality EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

calculated. The rate of stormwater This will require use of vegetated BMPs runoff, such as in cubic feet per second that will not only biologically uptake the (cfs) is a factor of the ten-year design nutrients and use them, but also uptake storm rainfall and the land cover over and break down many pesticides and which it fl ows. The volume of runoff herbicides into their non-hazardous is a factor not only of the design storm, components. but also of the land cover, particularly impervious and pervious surfaces. Oil, grease, chemicals, and heavy metals from vehicles are washed off of Likely Pollutants and Treatment parking lots and roadways during the Objectives fi rst few minutes of a rainstorm. These areas should be designed to drain Most commercial and housing into vegetated BMPs for fi ltering and development projects will generate water biological uptake before fl owing into the pollutants from vehicles, golf course and storm drainage system. lawn maintenance, and erosion. The primary pollutants from these sources Stormwater that runs off of rooftops are oil, grease, freon, other chemicals typically contains heavy metals, organic from vehicles, heavy metals, nutrients, materials, and coatings and other pesticides, herbicides, and sediment. components of the roofi ng materials. Rain gutter downspouts can carry Determining the treatment objectives rooftop runoff to stormwater BMPs. and designing the site treatment train are informed by both the source of Schematic Site Water Quality Impact each type of pollutant and the surface Study stormwater drainage patterns planned for the development. Knowing the source and type of pollutants, and determining the Sediment is caused by soil erosion, for treatment objectives, a site treatment which the fi rst defense is to prevent the train of BMPs can be developed. It erosion from occurring at all. Erodable involves simply following the stormwater soils and slopes should be stabilized where it falls and fl ows on the site, and and runoff should be diverted so it does creating areas for BMPs to treat the not fl ow over these slopes. The velocity water from erosion areas, turf areas, of runoff can be reduced to minimize vehicle areas, rooftops, and activity areas erosion. The area to which the sediment that generate pollutants. fl ows should be designed with a treatment area up stream of it to initially The example schematic Water Quality capture the sediment. Treatment Plan (see fi gure 10) shows the general areas where each type To minimize nutrients, pesticides, and and intensity of development will be herbicides from entering the stormwater, constructed, the direction of surface the best and fi rst line of defense is to drainage, and the treatment train of reduce the use of these chemicals in golf stormwater BMPs. When compared courses and lawn areas. See Chapter to the diagram of the pre-construction 4: Site Management and Maintance for site drainage, it shows how the site’s specifi c suggestions. Runoff from these existing hydrology is used as the basis areas should be treated in any case. for planning the development drainage. 14 Expected Pollutants by Activity / Use

oil grease freon heavy metals other Roadways and Parking Lots chemicals Lawn, Plantings, and Golf oil grease pesticides herbicides nutrients other Course Maintenance chemicals STORMWATER MANAGEMENT PLANNING PROCESS organic roofing coatings heavy metals Roofs and Gutters materials materials

oil grease freon heavy metals other Automotive Repair Shops chemicals

organic other Food Preparation materials grease chemicals

oil heavy metals other Commercial Buildings chemicals

organic pesticides herbicides other Residential Buildings materials chemicals

oil grease coatings heavy metals other Light Industrial chemicals Table 3: Likely Pollutants from Commercial and Housing Development Projects pollution by reducing runoff, but also Step 3: Prepare a Final Stormwater reduces infrastructure costs. If the Management Plan same number of homes are served by less street paving (shorter and narrower Now that the concepts for the site streets), the construction costs are development and stormwater treatment reduced. The cost of constructing train have been developed, the designer drainage, sewerage, and other can work out the site plan details while infrastructure will also be much lower. designing specifi c BMP components. Water Quality Impact Study The most effective means of minimizing stormwater pollution and runoff is to The site development plan, including minimize impervious surfaces. If natural stormwater management, were designed features of the site are conserved as and detailed based on the planned amenities in perpetuity, then the same treatement train diagrammed in the development intensity can be achieved Water Quality Treatment Plan (see by concentrating development in the fi gure 11) Note that in many areas areas most suitable for structures and of the project, stormwater BMPs are roadways. Denser and more clustered integrated into the site design, rather development means shorter road than placed off to the side, separate lengths. Roadway widths can also be from the development. For instance, minimized while following the EBR the boulevard entrances are planned Unifi ed Development Code (UDC). with biofi ltration medians, which are Reducing the lengths of driveways, bioswales into which the road slopes narrowing driveways, and providing and drains. Instead of continuous for shared parking in commercial areas curbing around the median, curb gaps minimizes impervious surfaces. at frequent intervals are employed to allow water to runoff the roadway, The results of this approach to site enter the biofi ltration median, and planning not only helps prevent water fl ow down the median instead of down 15 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

a gutter. The water is treated in the bioswale as it moves. See Chapter 5: Stormwater BMPs for more information on bioswales.

Summary of the Stormwater Management Planning Process

Step 1: Identify and Analyze Site Conditions

• Context • The development site • Existing Watershed and Surface Hydrology Map

Step 2: Preliminary Stormwater Management Plan (SMP)

• Prepare a Drainage Impact Study (DIS) • Prepare a Preliminary Water Quality Impact Study (WQIS) • Runoff rate and volume (post-construction) • Stormwater treatment train • Likely pollutants and treatment objectives • Schematic Water Quality Treatment Plan

Step 3: Final Stormwater Management Plan

• Prepare a Final Water Quality Impact Study • Final Water Quality Treatment Plan

16 STORMWATER MANAGEMENT PLANNING PROCESS 17 Figure 11: Step 3, Final Water Quality Treatment Plan Figure 10: Step 2, Schematic Water Quality Treatment Plan Figure 10: Step 2, Schematic Water EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Integrating BMPs into the Planning Process

On the following pages show examples of how to integrate BMPs into the site plan during the stormwater management planning process.

Figure 12: Typical roadway development

18 Figure 13: Roadway with a biofi ltration median STORMWATER MANAGEMENT PLANNING PROCESS 19 ow the soil ltrates into the stormwater from the street to fl into the median. There, plants use and clean the water before it drains into the stormwater system. Runoff is also reduced as water infi in the median. ltration median Below, section of a typical Instead of ltration devices. on a roadwayltration medians ltration median can act as fi closed curbs all around the median to retain the soil, the median is built at a lower elevation and curb gaps allow Water Quality Boulevard Biofi biofi Figure 14: Above, plan of a typical biofi EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

c

d g e

a b f

b e f g h

a pervious paved driveway b pervious paved sidewalk c pervious paved parking bays d street tree planting e biofiltration strip (sand filter under vegetation) f travel lanes g gapped curbs h non-compacted subgrade Figure 15: Above, plan of a typical roadway biofi ltration strip Below, section of a typical roadway biofi ltration strip

Water Quality Road into planted areas along the right-of- way. Local roads without on-street Local roads with or without on-street parking can drain through curb gaps into parking can help fi lter pollutants. Water planted areas. This strategy could also that would normally runoff into sewer be considered an infi ltration strategy as systems can be directed into pervious stormwater drains into planted areas and 20 parking along the street, and then drain pervious pavement into the soil below. STORMWATER MANAGEMENT PLANNING PROCESS 21 f bioswale e curb cuts d wheel stop wheel stop ltration strategy. ltration c paving, bioswales in the medians, and could include stormwater storage under the surface. Environmentally sensitive parking lots are also considered an infi e wheel stop/curb finishing options wheel stop/curb f biofiltration median b d c b pervious pavement a a Environmentally sensitive parking lots reduce the amount of non-pervious surface a typical parking lot presents. These parking lots include pervious Environmentally Sensitive Parking Lot Figure 17: Environmentally sensitive parking lot Figure 16: Diagram of a typical environmentally sensitive parking lot and drainage Figure 16: Diagram of a typical environmentally EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Figure 18: Diagram of a typical environmentally sensitive residential lot with a raised house

h g

e f

d

a c

b

a rain garden b bioswale c pervious paved driveway d air conditioning unit e rain gutters f rain barrell g amended soils h conservation area

22 Figure 19: Diagram of a typical environmentally sensitive residential lot with a slab house Water Quality Residential Lot Environmentally sensitive residential lots, also considered infi ltration and retention/detention strategies, concentrate on keeping stormwater on Office the property for longer periods. They Building include bioswales, rain gardens to STORMWATER MANAGEMENT PLANNING PROCESS fi lter the water, cisterns to store water for irrigation and outdoor uses, and pervious pavement. 5 acre detention pond

Figure 20: Typical development - lots, Water Quality Commercial Property parking, curbs gutters For commercial developments, the same principles apply. The offi ce building project in the following diagram was engineered with the typical approach. (see fi gure 20) As a result, the development would have to incorporate a fi ve-acre detention/ retention pond Office to handle the runoff from the rooftop Building and pavement. The pond was planned in a tight space directly across from the entrance to the development. This is clearly not an ideal situation, with fi ve acres of land dedicated to a rectangular 3+ acre detention pond pond with steep slopes and a chain link fence surrounding it. Figure 21: Stormwater BMP option - curb cuts, graded so water drains to islands As is often typical, the developer did not want to start the site planning process over because so much architectural and engineering work had already been pervious paving rain completed. The next two diagrams garden illustrate two ways in which a site bioswale plan that did not consider stormwater management from the beginning could be modifi ed to reduce stormwater Office runoff, improve water quality and, as a Building result, reduce the size of the required detention and retention pond. The fi rst solution merely modifi es grading of the parking lots. (see fi gure < 1 acre detention pond 21) Instead of sloping toward the center of the drive aisles, the paving is sloped Figure 22: Stormwater BMP integrated - away from the center and toward the pervious paving, bioswales, curb cuts, landscaped islands. The landscaped graded so water drains to islands 23 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

areas would be redesigned to be at a Benefi ts to Development lower elevation and with curb gaps so water fl ows from the impervious parking In considering the approach to site surface into raingardens and bioswales. development planning discussed in this Raingardens were also designed in open chapter, it is important to remember the areas around the perimeter of parking benefi ts: lots. Using stormwater runoff modeling, the fi rst solution showed the pond could • Conservation of green space and be reduced in size by over 20%. compactness of development provides fl exibility in the site design. The second solution for this commercial development utilized the grading and • More open space that serves drainage approach of the fi rst, and stormwater management also added two additional features which provides additional amenities. dramatically reduced the required size of the pond and further improved the • Conservation of the site’s natural and quality of water entering our water cultural features provides the bodies. (see fi gure 22) Pervious opportunity to create a unique concrete was designed for all the parking development with a strong sense of spaces. Although it has been proven to place. be durable and strong enough to be used for all the parking lot roadways as well, • These developments are in higher the developer’s engineer preferred that demand and can demand higher sales it not be used in travel lanes. In addition prices due to their unique character. to the pervious concrete which allows water to drain off the parking surface • Less infrastructure is required to be at a rate more rapid than any storm (up constructed. to 50 inches per hour), a manufactured subsurface retention storage system • Construction costs are reduced. was used. The soil excavated for the four-feet of subsurface storage system • Infrastructure maintenance costs are was used as fi ll under the building. The reduced. subsurface system was connected at the top to a pipe leading into the city’s stormwater system, serving as the outlet and as an overfl ow outlet. This design reduced the pond to less than one acre in size, reduced from original size (using the typical approach) by 80%. Perhaps the pond could have been eliminated altogether if the site plan had been designed from the start with stormwater management in mind.

24 CHAPTER 3 CONSTRUCTION PHASE CONSTRUCTION PHASE

Stormwater Pollution Prevention Plan An SWPPP document will identify potential sources of stormwater pollution A Stormwater Pollution Prevention Plan on the construction site and describe (SWPPP) is a site-specifi c document both BMPs and procedures that will that is required by the Environmental be implemented to reduce pollutants Protection Agency for construction and stormwater discharge at the sites that must comply with stormwater site. Construction site BMPs can be The contractor discharge requirements. This plan is structural or non-structural. is responsible more than just a sediment and erosion for preparing the control plan, but it describes all the In Louisiana, if you are building new SWPPP and its associated Notice activities needed to prevent stormwater construction, whether it is a subdivision, of Intent (NOI). contamination and comply with the commercial, or private property, if CONSTRUCTION PHASE requirements of the Clean Water you will disturb one acre or more of Act during construction. For more development, you must have a SWPPP information please visit: to receive a permit. The Louisiana Department of Environmental Quality http://www.epa.gov/Region8/water/ (LDEQ) has issued EBR Parish, stormwater/downloads.html Louisiana State University, and Southern University an overall stormwater http://www.deq.louisiana.gov/portal/ discharge permit, known as a National tabid/80/Default.aspx Pollutant Discharge and Elimination http://brgov.com/dept/dpw/environmental. htm System (NPDES) permit. This requires Figure 22: Lack of erosion prevention measures has allowed sediment to fl ow directly into the drain

Figure 23: Drain inlet protection employed to prevent sediment from entering the storm drain system 25 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

the parish to prevent polluted discharge of stormwater into any waterbodies within or adjacent to the parish. During the construction phase of a development project, the SWPPP is the means by which the parish ensures you do not violate the terms of their LDEQ permit. It is the responsibility of the contractor to prepare the SWPPP, implement it onsite, and inspect and maintain the BMPs Figure 25: Sediment control BMP - silt during the entire construction period. fencing

The contractor is Site Clearing BMP’s the parking of construction and workers legally obligated vehicles. to implement During site preparation and clearing, the the SWPPP, and contractor should plan early. Minimizing Erosion Control BMPs to inspect and the area that is disturbed is crucial maintain the to preventing stormwater pollution. Erosion control is intended to prevent BMPs during the There is no need to disturb site areas in soil particles from detaching and being entire construction transported in runoff. The fi rst and period. which construction will not take place. The construction area limits must be best means of accomplishing this is to identifi ed on the SWPPP. Soil disturbance minimize disturbed areas and to preserve and unprotected exposure should be existing vegetation and surface drainage minimized and and revegetated and patterns. In areas that must be disturbed, mulched as soon as possible. Protective temporary or permanent measures can zones should be established around prevent soil erosion. Erosion control valued natural resources, such as mature BMPs include establishing vegetation trees, wetlands, major tree stands, in disturbed areas as soon as possible, and wildlife habitat. No construction mulching, covering stockpiles, stabilizing activities should be allowed outside the the construction site entrances, and construction area limits, including the diverting runoff from disturbed areas. storage of materials and equipment and

Figure 26: Construction with erosion prevention measures

Figure 24: Construction activities in violation of the Water Quality Act

26 CONSTRUCTION PHASE 27 Figure 30: Protection against sediment Protection against Figure 30: by layering be increased runoff can such as a control measures sediment and silt fencing retention basin sediment maintenance which is crucial throughout the construction phase. Sediment control fences, BMPs include silt check dams, drain inlet protection, and sediment retention basins. BMPs to Control Water Runoff Drainage-ways should be stabilized through all construction phases to minimize increased erosion from in channels as needed or called for Additional temporary the SWPPP. swales and detention basins must be constructed to control runoff and resulting erosion. It may be possible after construction to convert these into permanent open channel systems by following the development site plan in creating temporary drainage ways. rst Figure 27: Erosion control BMPs must be Figure 27: Erosion construction to maintained throughout are functioning properly ensure that they Figure 29: Bank is being stabilized with erosion control matting Figure 28: Sediment from unstabilized bank has washed out onto the sidewalk Sediment control line of is the second defense because soil erosion has already occurred and the sediment must be stopped from site. These leaving the can be very effective, but require more effort than preventing erosion in the fi Sediment Control BMPs place. Sediment control involve BMPs removing of the as much as possible suspended soil particles from runoff. This requires proper and installation Vegetation plays a big role in erosion Vegetation control. success, establish For the most a vegetation as soon as possible after the soil and use an disturbance. Test appropriate mix for the particular seed time of year. EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Good Housekeeping Measures

The construction site SWPPP must be implemented prior to breaking ground at a construction site in order to protect the existing site. The construction site should be kept free from debris as much as possible. Spills from paint, oil, and chemicals used during construction can contaminate the soil and surrounding water bodies, so they should be disposed of offsite at the appropriate facilities in the parish.

28 CHAPTER 4 SITE MANAGEMENT AND MAINTENANCE SITE MANAGEMENT AND Maintaining the Stormwater MAINTENENCE Treatment Train General recommendations for The staff who will maintain and repair maintenance of each type of BMP are the development, once construction itemized in Table 4. is completed and the the property is in use, are key players in stormwater Good Housekeeping Measures management. They must ensure the stormwater treatment train continues to Practicing good housekeeping function in improving water quality, and in maintaining and operating the must practice good housekeeping on the development will minimize future property to prevent the introduction of problems and costs. Those addressed new pollution sources. below serve the primary goal of reducing pollution and waste in the The most important step is to prepare environment, particularly water and implement a maintenance program. pollution. Practicing these measures will As part of the design of BMPs, the also help developments comply with EPA landscape architect should prepare a water quality regulations. maintenance manual to assist staff in properly caring for the individual BMPs Cleaning and the entire stormwater treatment • Practice regular street sweeping to train. The maintenance manual should prevent litter build up. include specifi c information on when and • Clean structures and surfaces to how to maintain and replace vegetation, remove oil and grease. clean pervious paving, and prevent stormwater pollution when repairing Repairs and Storage and maintaining other parts of the • Do not store motor parts or equipment SITE MANAGEMENT AND MAINTENANCE development. containing grease, oil, or gasoline in

Table 4: General recommendations for maintenance of Stormwater BMPs 29 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

uncovered areas susceptible to runoff. • Replace dying, diseased, or damaged • Do not store uncovered or unsealed plants immediately trash or chemical containers in uncovered areas susceptible to runoff. The most important things to remember • Repair machines and vehicles in in site management and maintenance covered areas or on a pad of absorbent are that every action has the potential material to contain leaks, spills, and to prevent or reduce water pollution, discharges. and that a regular maintenance regime conducted by trained staff is a Water and Waste worthwhile investment. • Do not allow irrigation water to run off of the property. • Do not allow fl uids from washing or cleaning activities to run off of the property. • Dispose of waste and pollutants properly. • Recycle materials to minimize waste.

Plants • Use alternatives to herbicides, such as •keeping planted areas mulched (do not use cypress mulch, which is made from logging cypress in Louisiana’s coastal wetlands) •mowing grass to maintain higher grass, which is more competitive •leaving grass clippings which provide nutrients •water deeply and infrequently •planting native grasses or wildfl owers in large areas • Use alternatives to fertilizers, such as •compost •leave twigs and leaves on the ground under trees (not on lawns) • Use alternatives to pesticides, such as •diversify plant species •handpick pests off of plants early •set traps, such as: netting, can traps, and sticky boards •use benefi cial insects, such as butterfl ies and bees •use fi sh to control mosquitoes • Use low-toxicity pesticides 30 STORMWATER BMP’S 31 6 99 2 66 lter ow below ow CHAPTER 5 STORMWATER BMPs STORMWATER 5 CHAPTER 988 6 pper Zinc ian) Co d volume of ed out of the basin, ow gen ltration systems ltration o 74044 2 n/a itrite itrite 31 51 71 6 8 lters it before the water -14 4 itrate & itrate itr N val (Me val N N o les/usw_a.pdf

l gen ta o 8 o 33 43 57 T cacy of infi itr N ltration systems create a highly rus e l Retention systems areRetention permanent water that arebodies of to designed a specifi accommodate stormwater normal in excess of their then allow the systems levels. These to slowly percolateadditional water into the ground or fl which returnsits normal to level. water Infi porous surface layer that prevents runoff to quickly fl by allowing water the surface fi and percolates into the groundwater supply. The effi the is completely dependent upon permeability soil. of the Filtration systems collect and fi stormwater use of plants, with the sand, and/or gravel. They are often types of used in combination with other stormwater BMPs. For more information please visit: www.epa.gov/waterscience/guide/ stormwater/ www.epa.gov/waterscience/guide/ stormwater/fi llutant Rem llutant ho ub .0 25 4 2 88 551 33 6 35 30 8 66 o sp -

Sol ho P rus

l ho ta 9 9 9 o 4 5 sp T ho Percent P Percent P

l ids ta 1343 6 570 051 o 8 7 86 9 8 47 1 T Sol uspended ystems S of days. ed number S n o of hours, ed number and l ltration Systems, and es l nds nds n BMPs cacy of Stormwater BMPs ystems o fi n BMPs o ity Wet o S ystems l o swa S n n and Retenti o o BMP n rmwater o trati o Bi l Dry P trati Wet P Wet o l i trati F l Infi trati St l i Infi F Detenti Water Qua Water over a range of time. ow out of the basin Source, National Pollutant Removal Performance Database for STPs: 2nd Edition, www.cwp.org Database Performance for STPs: Removal National Pollutant Source, Table 5: Ef Detention systems are to hold designed water only during storm events, allowing the water to percolate the ground into or fl Some systems are to store designed water for a specifi while others a specifi with Either option can be accomplished an at surface (open) or below surface (closed) system. Detention and retentionsystems function as stormwater by providing BMPs places that collect stormwater and then slowly release time. it over a period of Best Management Practices (BMPs) Practices Best Management are a broad and range of methods procedures. These practices include pre-construction and post-construction urban to ruralimplementation, settings, hardscapeand landscape or composition. BMPs will be various In this chapter, in the following described and shown and Retention categories: Detention Systems, Infi Filtration Systems. STORMWATER BMPs STORMWATER EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

m l j k i Detention and Retention Systems a b c e f • Dry Pond g • Wet Pond d • Pond Edge with h Bulkhead • Pervious Paving with Manufactured Subsurface Storage a connection to stormwater management system b gravel bed c outflow pipe d slow infiltration e soil media f geotextile fabric g sand h non-compacted soil i wetland plants & natural grasses j forebay k rock headwall l inflow spray pipe m path Figure 31: Schematic Section of a Dry Pond

DETENTION AND RETENTION SYSTEMS Wet Pond

Dry Pond Wet ponds, also known as stormwater ponds or retention / detention ponds, Dry ponds, also known as detention are permanent bodies of water. Above ponds, are designed to hold water for the permanent water line is an area a minimum time and then completely in which water levels are allowed to drain. This allows pollutants to be fl uctuate as stormwater is detained. fi ltered by the vegetation along This area of water level fl uctuation is the edges and bottom on the pond. known as freeboard. The edges of wet Stormwater can then infi ltrate into the ponds, including the freeboard area, are soil or fl ow out of the basin slowly into a vegetated with plants that fi lter the water surface water body on closed drainage before it enters the pond. Wet ponds also system. treat water through particle settlement.

l n d j m a b c g k e h f i

a connection to stormwater management system b gravel bed c emergency spillway d path e amended soil f pond liner g freeboard h permanent wet pond i non-compacted soil j wetland plants & natural grasses k aquatic bench l forebay m rocks to reduce velocity & energy of flow n inflow pipe Figure 32: Schematic Section of a Wet Pond 32 Pond Edge with Bulkhead

Ponds in restricted spaces can still fi lter runoff from the surrounding areas. When bulkheads are used, the pond can receive water that fl ows through vegetation over the bulkhead. Water can also enter the pond through the amended soil and gravel, then through a permeable barrier below the bulkhead. This device is also serves to fi lter stormwater.

a

e b

c

d f

g STORMWATER BMP’S

a vegetated filter b amended soil c geotextile fabric d gravel e barrier/bulkhead f permeable barrier g undisturbed subgrade Figure 33: Schematic Section of Bulkhead

33 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Pervious Paving with Manufactured Subsurface Storage

Subsurface stormwater storage features hold stormwater below pervious pavement until it infi ltrates or drains into the groundwater or enters the closed drainage system. It is considered a detention area and can also act as fi ltration devices if fi ltration layers are included above the storage area.

a c

d

b e

f g a median/grass area b overflow safety pipe to stormwater system c concrete wheel stop or curb with curb gaps d pervious concrete or asphalt e manufactured subsurface storage device f pervious landscape fabric g non-compacted subgrade

Figure 34: Schematic Section of Subsurface Stormwater Storage Feature 34 INFILTRATION SYSTEMS

Pervious Paving A shallow base under pervious pavement allows for fi ltration of stormwater into Infi ltration Systems the soil below. This shallow aggregate should be used where the soil has a high • Pervious Paving infi ltration rate. If the aggregate under • Pervious Paving with Aggregate the pervious pavement holds too much Subsurface Storage water, a drain pipe will allow the excess • Infi ltration Device water to drain into the closed drainage • Cistern system. Curb gaps or wheel stops also allow water to fl ow into the median grass area to infi ltrate there.

a c

d

b e STORMWATER BMP’S

f g

a median/grass area b overflow safety pipe to stormwater system c concrete wheel stop or curb with curb gaps d pervious concrete or asphalt e aggregate with 40% void space f pervious landscape fabric g non-compacted subgrade

Figure 35: Schematic Section of Pervious Paving

35 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Pervious Paving with Aggregate Subsurface Storage

Pervious pavement allows infi ltration into the pavement and soil below whereas non-porous pavement causes water to immediately runoff into the drainage system. This allows water to be detained in the aggregate sub-base until it enters back into the groundwater and recharges aquifers or enters the closed drainage system. The technique is also considered a fi ltration device.

a c

d

b e

f g

a median/grass area b overflow safety pipe to stormwater system c concrete wheel stop or curb with curb gaps d pervious concrete or asphalt e aggregate with 40% void space f pervious landscape fabric g non-compacted subgrade Figure 36: Schematic Section of Pervious Paving with Aggregate Subsurface Storage

36 STORMWATER BMP’S 37 sand layer sand layer j i i gravel layer h lawn/vegetation lawn/vegetation stormwater infiltrates subsoil stormwater h e g d f e ltrate into the ground. irrigation pump/main line c Cistern A cistern, which captures rooftop runoff, serves several stormwaterIt functions. retains the runoff until it can be used. to Also, sediments in the water settle if the the bottom of the cistern. Finally, cistern is connected to a pump water and is used for site irrigation, it recycles the rainwater and allows it to eventually infi e sediment basin infiltration device c g d cistern ltration Device b d ltration overflow to storm drainage system overflowto storm j ltrates into ltrates c perforated pipe b c vegetative filter area area filter vegetative b rain gutter system system rain gutter f ltration device uses a a a b flows outward to the rest of the irrigation system rest of the irrigation system to the outward flows d sand trench sand trench rain gutter system system rain gutter e a ltration Device lter the water before it infi the ground. Manufactured infi systems, sometimes called stormwater leaching devices, are also available. perforated pipe, sand, and gravel to fi Large rooftop areas generate large amounts of stormwater runoff. When it either is impractical or undesirable to collect the rooftop runoff in a cistern or direct it to a raingarden or bioswale, to treatanother means should be used This infi the water. Infi Figure 38: Schematic Section of a Cistern Figure 37: Schematic Section of an Infi Figure 37: Schematic Section of EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

FILTRATION SYSTEMS

Bioswale Bioswales act as fi ltration devices in place of typical swales. Water is fi ltered by plants, sand, and gravel before entering into another BMP system or Filtration Systems into the closed drainage system and • Bioswale carried offsite. • Stormwater Planter with Permeable Base • Stormwater Planter with Impermeable Base • Sand Filter Basin • Catch Basin Insert • Water Quality Wetlands • Rain Garden • Green Roofs

a b c e d

h i f g

a native grasses b wetland plants c vegetated filtration swale d amended soil e path f pea gravel pocket surrounding entire drain pipe g perforated pipe (optional) h filter fabric around gravel pocket i non-compacted subgrade

Figure 39: Schematic Section of a Bioswale

38 STORMWATER BMP’S 39 h water tolerant plantings e and mulch to protect soil protect and mulch to k out topsoil/subsoil topsoil/subsoil p d g f inch sandy loam topsoil 8 e downs gravel as splash bloc 1 g g b draina ltrate h e ltrate into the overflow option minimum width of 12 inch a ltration or detention cd b it, and use it as lter a lteredto infi then allowed reservoir depth should be 4-12 inches f gravel/recycled glass with gravel/recycled c Figure 40: Schematic Section of a Permeable Stormwater Planter Stormwater Planters are to designed fi take roof water, irrigation the site. Excess for plants on water is fi Stormwater Planter 1 Stormwater Permeable into the soil to help rechargeinto the soil to help the This technique could also groundwater. be considered an infi it holds the stormwaterdevice because slowly infi and allows it to closed drainage system. soil or enter the EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Stormwater Planter 2 impermeable Stormwater Planters are designed to take roof water, fi lter it, and use it as irrigation for plants on the site. If conditions do not allow permeable surfaces below the planter for infi ltration, a drainage pipe can be added at the bottom to collect and convey fi ltered water for reuse, to a raingarden or bioswale or to a closed drainage system.

e j

g

f d

b

c

h

k a

a foundation drains as required b waterproof building as needed c 12 inch gravel/sand d 18 inch sandy loam topsoil e downspout f stone or mulch to protect soil g reservoir 4-12 inches in depth h perforated pipe j reverse bend trap k pipe to main storm system Figure 41: Schematic Section of a Impermeable Stormwater Planter

40 Sand Filter Basin

Sand Filter Basins are designed as a two chambered device with the fi rst chamber designed for the settlement of large particles and the second chamber designed for fi ltering smaller particles and other pollutants. The fi ltered water then fl ows out of the discharge pipe into a pond or other waterbody.

a h

b j cig

k

d l e m f

a grated lid b inflow pipe c sedimentation chamber d low flow outlet pipe with filter screen e accumulated heavy sediments/debris f reinforced concrete slab g overflow barrier h access cover i sand filter chamber j overflow discharge pipe k sand filter media l clean gravel layer m perforated pipe

Figure 42: Schematic Section of a Sand Filter Basin STORMWATER BMP’S

41 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Catch Basin Insert

Catch Basin Inserts are manufactured devices used to capture settlement and debris from stormwater before fl owing through the system. These are usually used as pretreatment for other practices by catching large sediment particles. The fi ltered water then fl ows out of the discharge pipe into a pond or other waterbody.

a

b c

d

f

e

a catch basin grate b insert c oil absorbant material d media housing e treated stormwater f outlet pipe Figure 43: Schematic Section of a Catch Basin Insert

42 abcde f g

a open water (3 - 7 feet) b deep marsh (1.5 - 3 feet) c shallow marsh (0.5 -1.5 feet) d wet meadow (0 - 6 inches) e scrub/shrub wetland f forested wetland g upland buffer Figure 44: Schematic Section of a Water Quality Wetland

Water Quality Wetlands plant material along the way. Smaller wetland forebays can also be designed to Constructed wetlands provide for a fi lter water runoff. progressive cleaning of stormwater before it drains into surface water. As it fl ows from forested areas to marshes, the stormwater is fi ltered and cleaned by STORMWATER BMP’S

Figure 45: Schematic Section of a Rain Garden

Rain Garden non-toxic elements. Rain Gardens can vary in size and design based on the Rain Gardens are depressed landscaped area that drains into it and the type of areas that detain and treat stormwater soil in which it is implemented. As an runoff. Water is directed into the option, perforated pipes can be installed gardens by pipes, swales or curb below the rain garden soil and connected openings. While the water is detained, to the closed drainage system. They can sediments settle to the bottom, water be cared for as either gardens or can be is used by the plants, and plants uptake blended into the landscape making them pollutants and either hold them in their look “natural.” Many native Louisiana tissues or break them down into plants grow and thrive in rain gardens. 43 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Green Roof membrane adds additional protection upon which a drainage mat lays, Green roofs are designed to intercept providing space for water that is not rainwater that falls on a roof, allowing used by the plants to drain. The fi lter plants to fi lter and uptake the water. fabric prevents the growth media from clogging the drainage area. The growth Green roofs provide a number of media is designed to be light in weight, benefi ts: to retain water for use by plants, and to • reduced stormwater runoff provide plant nutrients. Locally available • higher quality of runoff water rice hulls are light and retain water, • less extreme roof temperatures so are an excellent component of the • reduced BTU consumption in growth media. The vegetation planted the building on the green roof can vary signifi cantly, • extended life of the roof from native grasses to species tolerant of drought and wind, fl uctuating The thickness of the green roof structure temperature, and full sun conditions. can vary by design, but need not be A licensed landscape architect should substantial in thickness or weight. On design the planting and the growth top of the existing roof, a waterproof media for the green roof.

f

e

d c b a

a bituminous roof b waterproof membrane c drainage mat d soil filter fabric e growth media f vegetation

Figure 46: Schematic Section of a Green Roof

44 Slanted roofs can be retrofi tted as green roofs using technology similar to fl at roofs, but the drainage system has to accomodate more rapid rate of runoff and the roof edges must be retrofi tted to contain the green roof system.

f

e

d

c

b

a STORMWATER BMP’S

a shingle roof b waterproof membrane c drainage mat d soil filter fabric e growth media f vegetation Figure 47: Schematic Section of a Slanted Green Roof

45 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Green roofs can be installed or retrofi tted on many roof types including: concrete, shingle, bituminous, slate, and asphalt.

h

a f b g

c e

d

a concrete roof b primed substrate c water proof membrane d root protection barrier e protection board f filter fabric g growth media h vegetation Figure 48: Schematic Section of a Concrete Green Roof

46 RESOURCES FOR STORMWATER BMPs RESOURCES FOR STORMWATER BMPs

Websites City Parish Contacts

The following represent a small sampling of City Parish Planning Commission useful stormwater-related information. [email protected]

American Institute of Hydrology Department of Public Works www.aihydro.org [email protected]

American Society of Landscape Architects www.asla.org

Baton Rouge Department of Public Works http://brgov.com/dept/dpw

Center for Watershed Protection www.cwp.org

Environmental Protection Agency www.epa.gov

Environmental and Water Resources Institute of ASCE www.ewrinstitute.org

International Stormwater Best Management Practices Database www.bmpdatabase.org

Louisiana Department of Environmental Quality www.deq.louisiana.gov

Louisiana State University Ag Center www.lsuagcenter.com/en/environment/ water_issues/quality/

Natural Resources Defense Council www.nrdc.org

River Network RESOURCES www.rivernetwork.org

Smart Growth Online www.smartgrowth.org

Stormwater Authority www.stormwaterauthority.org

47 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Reference Books Melbourne Water Corporation. Melbourne Water Land Development Manual. Water These books and articles offer Sensitive Urban Design. the implementation of Best Management Practices and Smart Growth. Mendler, Sandra. Reexamining the Future for Sustainable Design. DesignIntelligence. Greenway Group, Design Futures Council.

Construction Minton, Gary R. 2005. “Revisiting Design Criteria for Stormwater Treatment Systems, Part 3: Flow-Through Treatment Swales and Strips.” Stormwater: The Journal Environmental Stewardship Practices, for Surface Water Quality Professionals. 2004. Procedures, and Policies for Highway March/April 2005 Issue, Volume 6, Number Construction and Maintenance. Veneer 2, p 28-43. Consulting and Parsons Brinckerhoff. Ernst, Caryn and Hart, Kelley. Webendorfer, Bruce, editor. 2002. Rain Gardens: A Household Way to Improve Wisconsin Department of Natural Water Quality in Your Community. Resources. 2004. Temporary Grading University of Wisconsin—Extension and Practices for Erosion Control: Surface Wisonsin Department of Natural Resources, Roughening and Temporary Ditch Sumps, Madison, WI. Conservation Practice Standard. Wong, Tony; Breen, Peter; and Lloyd, Sarah. Wisconsin Department of Natural 2000. Water Sensitive Road Design: Design Resources. 2003. Vegetative Buffer for Options for Improving Stormwater Quality of Construction Sites, Construction Practice Road Runoff. Cooperative Research Centre Standard. for Catchment Hydrology.

Design Green Space, Green Infrastructure, and Conservation Chadde, John; Rulison, Linda; Smith, Ruth Ann; and Dunstan, Jean. 2005. Design Curran, Deborah. 2001. Economic Benefi ts Guidelines to Enhance Community of Natural Green Space Protection. The Appearance and Protect Natural Resources. POLIS Project on Ecological Governance, Western Upper Peninsula Center for Eco Research Chair of Environmental Science, Mathematics, and Environmental Law and Policy, Faculty of Law and School Education and Michigan Technological of Environmental Studies, University of Uinviersity, Houghton, MI. Victoria, Canada; and Smart Growth British Columbia. Melbourne Water and Knox City Council. 2002. Water Sensitive Urban Design: For Large Scale Developments or Small Scale/ One Off Projects.

48 Dudley, Nigel and Stolton, Sue. 2003. Running Pure: The Importance of Forest Prigann, Herman and Strelow, Heike, editor. Protected Areas to Drinking Water. World 2004. Aesthetics of Ecology. Birkhauser Bank and WWF Alliance for Forest Verlag. Conservation and Sustainable Use. Ecological Engineering, WBM, and Parsons Rushton, Betty, Ph.D. 2002. Infi ltration Brinckerhoff. 2004. WSUD Engineering Opportunities in Parking Lot Designs Procedures: Stormwater, Draft. Reduce Runoff and Pollution. Seventh Biennial Stormwater Research and Ernst, Caryn. 2004. Protecting the Source: Watershed Management Conference, May Land Conservation and the Future of 22-23, 2002. America’s Drinking Water. The Trust for Public Land. The Conservation Fund, Land Advisory Services. Talbot County Green Graduate Student Workshop. 2002. Linking Infrastructure Plan, Talbot County, MD. Natural and Historic Assets: Green Infrastructure as Economic Development in The Federal Interagency Stream Restoration Lenior County, North Carolina. Department Working Group. 1998. Stream Corridor of City and Regional Planning, University of Restoration: Principles, Processes, and North Carolina at Chapel Hill. Practices. National Engineering Handbook, Part 653. Harrison, Tracy and Mitchell, David. 2001. Environmental Management Tyne, Ron. 2000. Bridging the Gap: Plan: Thurgoona Campus. School of Developers Can See Green, Economic Environmental and Information Sciences for Benefi ts of Sustainable Site Design and Low- the Johnston Centre, Division of University Impact Development. Land Development Properties; and Albury Wodonga Campus, Journal, p. 27-31. Charles Sturt University.

Head, Constance P.; Fisher, Robinson; and O’Brien, Maureen. 2001. Best Management Planning Practices for Community Trees: A Technical Guide to Tree Conservation in Athens- Clarke County, Georgia. A Design Approach to Reduce Stormwater Impacts from Land Development and Hoff, Mary, editor. 2000. Conserving Achieve Multiple Objectives Related to Wooded Areas in Developing Communities: Land Use. 1997. Department of Natural Best Management Practices in Minnesota. Resources and Environmental Control; and Hopper, Kim, editor. 2002. Local the Environmental Management Center of Greenprinting for Growth, Volumes I-IV. the Brandywine Conservancy. The Trust for Public Land. Blaha, Kathleen A.; Cogan, Jessica; Stein, Maynard, Roberta. 2000. “Natural Selection: Linda; and Ward, Matt. 2003. Smart Growth Why developers are going all out to protect RESOURCES for Clean Water: Helping Communities trees and other natural features”. Big Address the Water Quality Impacts of Builder. March 2000 Issue, p 26-36. Sprawl. National Association of Local Government Environmental Professionals, Poole, William, editor. Building Green Trust for Public Land, and ERG. Infrastructure: Land Conservation as a Watershed Protection Strategy.

49 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Byers, Elizabeth and Ponte, Karin Marchetti. Weinstein, Neil. 2002. Low Impact 2005. The Conservation Easement Development Retrofi t Approach for Urban Handbook, Second Edition. Land Trust Areas. Seventh Biennial Stormwater Alliance and The Trust for Public Land. Research and Watershed Management Conference. Ernst, Caryn. 2001. Smart Growth, Land Conservation, and Clean Water. Getting Smart, Volume 4, Number 1. Stormwater Management France, Robert L. Lawrence. 2002. Handbook of Water Sensitive Planning and Design. A Systematic Approach to Drainage. 2005. Stormwater: The Journal for Surface Water Gordon, Nancy D., Finlayson, Brian L., Quality Professionals. March/April 2005 Gippel, Christopher, J., Nathan, Rory J., Issue, Volume 6, Number 2, p 80-81. and McMahon, Thomas A. 2004. Stream Hydrology: An Introduction for Ecologists. Allison, Robin; Chiew, Francis; and Wiley, John and Sons, Inc. McMahon, Tom. 1997. Stormwater Gross Pollutants: Industry Report. Cooperative Hough, Michael. 1995. Cities and Natural Research Centre for Catchment Hydrology. Processes. Routledge, New York, NY. Arendt, R.G. 1996. Conservation Design Low-Impact Development Design Strategies: for Subdivisions. Natural Lands Trust, An Integrated Design Approach. 1999. American Planning Association, and Prince George’s County, Maryland American Society of Landscape Architects. Department of Environmental Resource, Backstrom, M. 2002. Programs and Planning Division. Christov A-Boal, D.; Lechte, P.; and Ndubisi, Forster. 2002. Ecological Planning: Shipton, R. 1995. Installation and A Historical and Comparative Synthesis. Evaluation of Domestic Greywater Reuse Johns Hopkins University Press. Systems. Department of Civil and Building Parsons Brinckerhoff. 2004. Sustainable Engineering; and Victoria University of Development. PB Network, Issue No. 59, Technology, Victoria, Australia. November 2004, Volume XIX, Number 3. First Annual Report: Mitigating Nonpoint Schueler, T. R. 1995. Environmental Source Pollution in Urban Watersheds with Land Planning Series: Site Planning for Spatial Modeling, 2004. Best Management Urban Stream Protection. Department for Practices for Wetlands and Community Environmental Programs, Metropolitan Outreach. School of the Coast and Washington Council of Governments, Environment, Louisiana State University, Washington, D.C. Baton Rouge, LA.

The Guiding Principles of the Ranch Plan. GeoSyntec Consultants, Urban Drainage Rancho Mission Viejo, Orange County, and Flood Control District, Urban Water CA. Monitoring: A Guide for Meeting the National Stormwater BMP Database Requirements. Offi ce of Water, US Environmental Protection Agency. 50 RESOURCES 51 ce Wetlands Bastian, Robert K. 1993. Constructed Treatment and for Wastewater Wetlands Wildlife Offi States EPA Habitat. United Sediment TransportSediment Swales in Grassed RunoffDuring Simulated Events. Water 45, Journal,and Technology Science Volume No.7. R. and Drinan, Joanne, Spellman, Frank StormwaterE., editors. 2003. Discharge Practical Guide to Management: A Compliance. Government Institutes, Rockville, MD. 2002. Out of the Jr. James W. Woodworth, Polluted RunoffGutter: Reducing in the District of Columbia. Natural Resources Defense Council. Management. of Wastewater Gelt, Joe. 1997. Constructed Wetlands: Natural Processes Using Human Ingenuity, Build Habitat. Arryo.to Treat Water, March 9, Number 4. 1997 Issue, Volume on Wetland Interagency Workgroup Restoration. An Introduction and User’s Restoration, Creation, and Guide to Wetland Enhancement. Somes, Breen, Peter F.; H. F.; Tony Wong, Nicholas L. G.; and Lloyd, Sarah D. 1999. Managing Urban Stormwater Using IndustryConstructed Wetlands: Report. Cooperative Research Centre for Catchment Victoria, Australia. Hydrology, t Roy, Steven P.; Quigley, Marcus M.; and Quigley, Steven P.; Roy, Danos, Savos. 2002. Stormwater Retrofi Ree, W.O. 1949. Hydraulic Characteristics Ree, W.O. Waterways. for Vegetated of Vegetation Agricultural Engineering Journal, S 671 A3, 30. Volume Path to Protection: Ten Strategies for Path to Protection: Ten Protection. 2005. Successful Source Water Protection Series. TrustWater for Public Land. of Long Lake, Littleton, MA—Using Low Impact Development Approaches. Seventh Biennial Stormwater Research and Management Conference, May Watershed 22-23, 2002. Nathanson, Jerry A. 1986. Basic Supply, Water Environmental Technology: and Pollution Control. Disposal, John Waste NY. Wiley and Sons, New York, Mitchell, Grace; Mein, Russell; and Mitchell, Grace; Mein, Russell; and 1999. The Reuse Potential McMahon, Tom. of Urban Stormwater and Wastewater. Cooperative Research Centre for Catchment Hydrology. Melbourne Water Corporation. 2003. Corporation. Melbourne Water Handbook. Recycled Water Marsalek, Jiri; Zeman, Evzen; Watt, W. Ed; W. Evzen; Watt, Marsalek, Jiri; Zeman, Heiko. 2001. Advances in Urban and Seiker, Stormwater and Agricultural Runoff Source Earth Controls. NATO Science Series IV, 6. and Environmental Sciences Volume Kluwer Academic Publishers. Louisiana Water Quality Management Plan. Quality Management Louisiana Water Louisiana Department of Environmental Gleason, John. 2004. AlternativeGleason, Stormwater Management Techniques. Protection and Watershed City of Austin, Review Department,Development Austin, TX. EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

52 GLOSSARY OF TERMS

Abatement Reducing the degree or intensity of, Drainage Impact Study (DIS) A component or eliminating, pollution. of the Stormwater Management Plan required by the stormwater management planning process. Acute Toxicity The ability of a substance to cause severe biological harm or death soon after Drainage structure A human-made structure a single exposure or dose. Also, any poisonous that facilitates the movement of water off an area. effect resulting from a single short-term exposure to a toxic substance. Dredging Removal of mud from the bottom of waterbodies. This can disturb the ecosystem and Agricultural Pollution Farming wastes, cause silting that kills aquatic life. Dredging of including runoff and leaching of pesticides contaminated muds can expose biota to heavy and fertilizers; erosion and dust from plowing; metals and other toxics. improper disposal of animal manure and carcasses, crop residues, and debris. Dry Pond A facility that provides stormwater quantity control by containing excess runoff in Aquifer An underground geological formation, a detention basin, then releasing the runoff at or group of formations, containing water. Are allowable levels. sources of groundwater for wells and springs. Ecosystem The interacting system of a Assimilation The ability of a body of water to biological community and its non-living purify itself of pollutants. environmental surroundings.

Basin Any area draining to a point of interest. Edge An area where two or more vegetation types converge. Best Management Practice (BMP) Methods that have been determined to be the most Erosion The wearing away of land surface effective, practical means of preventing or by wind or water, intensifi ed by land-clearing reducing pollution from nonpoint sources. practices related to farming, residential or industrial development, road building, or logging. Bioswale A long, gently sloped, vegetated ditch designed to fi lter pollutants from stormwater. Eutrophication The slow aging process during native grasses are the most common vegetation, which a lake, estuary, or bay evolves into a bog but wetland vegetation can be used if the soil is or marsh and eventually disappears. During the saturated. later stages of eutrophication the waterbody is choked by abundant plant life caused by higher Buffer strip A relatively undisturbed section levels of nutritive compounds such as nitrogen of forest adjacent to an area requiring special and phosphorus. Human activities can accelerate attention or protection such as a stream, lake, or the process. road. Evapotranspiration The process of Channel A natural stream which conveys transferring moisture from the earth to the surface runoff water within well-defi ned banks. atmosphere by evaporation of water and transpiration from plants. Culvert A metal, concrete, or plastic pipe through which water is carried. Filter strip A vegetated area of land that fi lters runoff and separates a water body from activities Detention The temporary storage of that generate runoff; or a vegetated area that stormwater runoff in a BMP with the goals of collects, fi lters, and conveys water much like a controlling peak discharge rates and providing bioswale.

gravity settling of pollutants. GLOSSARY Filtration A water treatment process for Discharge Flow of surface water in a stream removing solid (particulate) matter and other or canal or the outfl ow of groundwater from pollutants from water by means of porous media a fl owing artesian well, ditch, or spring. Can such as sand, a man-made fi lter, or vegetation. also apply to discharge of liquid effl uent from a facility or to chemical emissions into the air through designated venting mechanisms. 53 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

GIS (Geographic Information Systems) Integrated Stormwater Management An A set of powerful tools that visualize and approach which regards stormwater as a manage large data sets with complex spatial resource rather than as waste which must be and physical interactions. GIS helps identify disposed of. potential problems and solutions, and facilitates alternatives and analysis using maps and other Invasive Species Introduced species or non- graphics depicting the outcome of each modeled indigenous species that are rapidly expanding alternative. outside of their native range.

Gray Water Domestic wastewater composed Load Allocation (LA) The portion of a of wash water from kitchen and laundry sinks, receiving water’s total maximum daily load tubs, and washers. Does not include toilet water that is attributed either to one of its existing or (black water). future nonpoint sources of pollution or to natural background sources. Groundwater The fresh water found beneath the Earth’s surface, usually in aquifers, which Maximum Daily Load The maximum pollutant supplies wells and springs. Because groundwater load that a body of water can safely accommodate is a major source of drinking water, there is and meet water quality standards. growing concern over contamination from leaching agricultural or industrial pollutants or Mitigation Measures taken to reduce adverse leaking underground storage tanks. impacts on the environment.

Groundwater Discharge Groundwater Native Species Originating naturally, growing entering near coastal waters which has been or produced in a particular country or region, as contaminated by landfi ll leachate, deep well animals or plants. injection of hazardous wastes, septic tanks, etc. Natural Channel A watercourse created by Habitat The place where a population (e.g., the erosive forces of water moving over land. human, animal, plant, microorganism) lives and Drainage ditches are not considered natural its surroundings, both living and non-living. channels.

Hazardous Waste By-products of society Natural Drain A naturally occurring that can pose a substantial or potential hazard conveyance for he fl ow of water. to human health or the environment when improperly managed. Possesses at least one Natural Regeneration The planned of four characteristics (ignitability, corrosivity, regeneration of a forest that either uses existing reactivity, or toxicity), or appears on special EPA trees as a source of seed or encourages sprouting lists. from stumps or roots.

Heavy Metals Metallic elements with high Nonpoint Source Pollution (NPS) Pollution atomic weights; (e.g. mercury, chromium, which is induced by runoff; is not traceable cadmium, arsenic, and lead); can damage to any discrete or identifi able facility; and is living things at low concentrations and tend to controllable through the utilization of best accumulate in the food chain. management practices.

Hydromodifi cation The alteration of the Nonpoint Sources Diffuse pollution sources natural fl ow of water through a landscape, and (i.e., without a single point of origin or not often takes the form of channel modifi cation or introduced into a receiving stream from a specifi c channelization. outlet). The pollutants are generally carried off the land by stormwater. Common nonpoint Hydrology The science dealing with the sources are agriculture, forestry, urban, mining, properties, distribution, and circulation of water. construction, dams, channels, land disposal, saltwater intrusion, and city streets. Infi ltration The penetration of water through the ground surface into sub-surface soil. The technique of applying large volumes of waste water to land to penetrate the surface and 54 percolate through the underlying soil. Nutrient Any substance assimilated by living Remediation Cleanup or other methods used things that promotes growth. The term is to remove or contain a toxic spill or hazardous generally applied to nitrogen and phosphorus in materials. wastewater, but is also applied to other essential and trace elements. Retention The process of collecting and holding surface and stormwater runoff with no Nutrient Pollution Contamination of water surface outfl ow. The amount of precipitation on a resources by excessive inputs of nutrients. In drainage area that does not escape as runoff. surface waters, excess algal production is the major concern. Retrofi t Addition of a pollution control device on an existing facility without making major Operation and Maintenance BMPs changes to the generating plant. Activities conducted after construction to ensure that facilities constructed to treat runoff Runoff That part of precipitation, snowmelt, water will be properly operated and maintained or irrigation water that runs off the land into to be effective and effi cient in stormwater streams or other surface water. It can carry management. pollutants from the air and land into receiving waters. pH An expression of the intensity of the basic or acid condition of a liquid; may range from 0 to 14, Sediments Soil, sand, and minerals washed where 0 is the most acid and 7 is neutral. Natural from land into water, usually after rain. They pile waters usually have a pH between 6.5 and 8.5. up in reservoirs, rivers and harbors, destroying fi sh and wildlife habitat, and clouding the water Phosphorus An essential chemical food so sunlight cannot reach aquatic plants. Careless element that can contribute to the eutrophication farming, mining, and construction activities will of lakes and other waterbodies. Increased expose sediment materials, allowing them to phosphorus levels result from discharge of wash off the land after rainfall. phosphorus-containing materials into surface waters. Stormwater Precipitation that accumulates in natural and/or constructed storage and storm Phytoremediation Low-cost remediation option water systems during and immediately following for sites with widely dispersed contamination at a storm event. low concentrations. Surface Water All water naturally open to the Point Source A stationary location or fi xed atmosphere (rivers, lakes, reservoirs, ponds, facility from which pollutants are discharged; any streams, impoundments, seas, estuaries, etc.). single identifi able source of pollution; e.g., a pipe, ditch, ship, ore pit, factory smokestack. Suspended Solids Small particles of solid pollutants that fl oat on the surface of, or are Potable Water Water that is safe for drinking suspended in water. and cooking. SWM Storm Water Management Rain Garden A low-lying garden that intercepts stormwater runoff, fi lters it, and allows for SWPPP Storm Water Pollution Prevention Plan percolation of water back into the groundwater (required by Louisiana Department of supply Environmental Quality)

Receiving Waters A river, lake, ocean, stream, TMDL (Total Maximum Daily Load) The or other watercourse into which wastewater or allowable loadings or other quantifi able

treated effl uent is discharged. parameters for a waterbody to meet the U.S. GLOSSARY EPA’s TMDL Program, authorized under Section Recharge Zone A land area in which water 303(d) of the Clean Water Act (CWA), water reaches the zone of saturation from surface quality standards. The CWA addresses waters in infi ltration, e.g., where rainwater soaks through the nation that do not meet the national goal of the earth to reach an aquifer. “fi shable, swimmable,” despite implementation of nationally required levels of control pollution technology that requires each state to identify and develop TMDLs. 55 EAST BATON ROUGE MASTER DEVELOPMENT PROGRAM

Total Suspended Solids (TSS) A measure of the suspended solids in wastewater, effl uent, or waterbodies, determined by tests for “total suspended non-fi lterable solids.”

Uptake The absorption by plant tissues of a substance, such as a nutrient, and its permanent or temporary retention.

Urban Runoff Stormwater from city streets and adjacent domestic or commercial properties that carries pollutants of various kinds into the drainage systems and receiving waters.

Wastewater The spent or used water from a home, community, farm, or industry that contains dissolved or suspended matter.

Water Quality Impact Study (WQIS) A component of the Stormwater Management Plan required by the stormwater management planning process.

Water Quality Standards (WQS) State- adopted and EPA-approved ambient standards for waterbodies. The standards prescribe the use of the waterbody and establish the water quality criteria that must be met to protect designated uses.

Watershed Approach A coordinated framework for environmental management that focuses public and private efforts on the highest priority problems within hydrologically defi ned geographic areas (watersheds) taking into consideration both surface and groundwater fl ow.

Watershed The land area that drains into a stream; the watershed for a major river may encompass a number of smaller watersheds that ultimately combine at a common point. At the larger scale, East Baton Rouge Parish is in the Lake Ponchartrain Basin (watershed) and one- third of the U.S. drains into the Atchafalaya Basin (watershed).

Wetlands An area saturated by surface or groundwater with vegetation adapted for life under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.

Wet Pond A facility that treats stormwater for water quality by utilizing a permanent pool of water to remove conventional pollutants from runoff through sedimentation, biological uptake and plant fi ltration. 56