FOR-73   Creating Urban Stormwater Control Ponds for         Water Quality and Wildlife Habitat                           ...
Water Quality                                                             Maintenance needs differ between the two structu...
wildlife. Shallow areas are also necessary to establish aquatic         will eventually develop vegetation, it will do so ...
ments with gently sloping sides are also safer than steep-            Water quality can be enhanced by a flow-through syst...
Zone 3: Pond Shoreline (water tolerant but can be             Zone 4: Riparian Fringe (must be able to tolerateexposed for...
No trees on embankment.                                                                                                   ...
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KY: Creating Urban Stormwater Control Ponds for Wildlife Habitat and Water Quality

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Creating Urban Stormwater Control Ponds for Wildlife Habitat and Water Quality

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KY: Creating Urban Stormwater Control Ponds for Wildlife Habitat and Water Quality

  1. 1. FOR-73 Creating Urban Stormwater Control Ponds for Water Quality and Wildlife Habitat Thomas G. Barnes, Extension Wildlife Specialist Lowell Adams, National Institute for Urban WildlifeW etlands are important wildlife habitats, and they pro- vide numerous benefits and services to society. Natu-ral wetlands help replenish groundwater supplies, act as natu- gineering and hydrologic information, contact the local Natu- ral Resources Conservation Service and ask for a copy of their publication, Ponds—Planning, Design, Construction.ral pollution filters, purify water, control erosion, lessen the You may also want to obtain a copy of Guidelines for Streamimpact of flooding, provide food and fiber for humans, and and Wetland Protection in Kentucky from the Kentucky Di-offer countless opportunities for education and recreation. vision of Water (14 Reilly Road, Frankfort, KY 40601). ThisBecause they are so important to wildlife, wetlands have been publication compares detention and retention ponds, two ofcalled “nature’s cities.” Unfortunately, people have not val- the most common stormwater control structures used today,ued wetland systems, and more than 80 percent of Kentucky’s and provides information on how to design these structureswetlands have been drained, filled, or destroyed. Nationally, to benefit waterfowl and other wildlife.we have destroyed more than 50 percent of our wetlands. Water is often a factor that limits the types, numbers, andabundance of wildlife in urban environments. In the past, Stormwater Control Structureswe destroyed natural wildlife water sources, such as wet- The two types of structures most commonly used to con-lands and ponds, to make way for development. Before land trol urban stormwater are “dry” ponds, also known as deten-is developed, rainwater is intercepted by vegetation and in- tion ponds, and “wet” ponds, also known as retention ponds.filtrates the soil. After development, driveways, rooftops, As their names imply, the major difference is the length ofand other impervious surfaces reduce the infiltration capac- time water stands in the pond. Dry ponds are designed toity of the soil. Unable to percolate into the soil, rainwater collect water during a storm and then release this water at amoves over the area, with the potential to damage property predetermined rate to a nearby body of water. They are gen-and cause floods. erally dry between storms. Wet ponds are designed to con- As water runs over roads, sidewalks, and parking lots, it tain water on a year-round basis. Although both types ofpicks up a number of pollutants including oil, grease, and structures control stormwater and reduce the risk of flood-heavy metals such as lead, zinc, copper, and mercury. Rain- ing, wet ponds are much better at improving water qualitywater that flows over lawns picks up nitrogen, phosphorous, and providing wildlife habitat.and pesticides from lawn care products. Stormwater runoff Some of the costs and benefits of creating a detention orwith its load of pollutants eventually reaches local streams retention pond are discussed below.where it deposits pollutants and increases the volume andvelocity of stream water, resulting in greater stream contami-nation, channelization, erosion, and sedimentation. As a re- Feasibility for the Sitesult, fish and other aquatic life inhabiting these streams are The first step in choosing and designing a stormwateroften reduced in numbers or eliminated altogether. structure is to determine which designs are feasible for the In response to these problems, thousands of structures have site description, soil type, and local geology. Wet ponds gen-been built throughout the United States for the purpose of erally require more space than dry ponds, so they are notcontrolling stormwater. However, in the past, little consid- recommended for small areas.eration was given to structural designs that would also ben- Soil permeability also influences which structures will beefit wildlife and improve water quality. The challenge to most successful. For example, dry ponds work best in areasplanners, engineers, and surveyors today is to design struc- with extremely permeable sandy soils, but wet ponds are thetures that will control stormwater and also improve water better choice in areas with heavy clay soil where drainage isquality and provide wetland and wildlife habitat. poor. The purpose of this publication is to provide information The local geology can also influence the design choice.for developers and government policy makers on creating a Wet ponds require extensive excavation and are more diffi-type of water source that will benefit wildlife and control cult to create in areas where the underlying bedrock is closestormwater discharge. This information can also be used by to the surface.developers when creating ornamental ponds at the entrancesto new subdivisions and other public areas. For specific en-
  2. 2. Water Quality Maintenance needs differ between the two structures. For instance, dry ponds maintained as the law requires need more Stormwater may contain many pollutants, including sedi- frequent mowing and removal of trash. In addition, fertilizerment and heavy metals that exist in particulate form and used on the lawn contributes to the already excessive nutri-soluble pollutants such as nitrogen and phosphorus. For a ent loads in downstream water. Wet ponds require less rou-variety of reasons, wet ponds are much better than dry ponds tine maintenance; however, sediment removal is neededat removing both types of pollutants and thereby improving approximately every ten to twenty years, and this can be ex-water quality. Sediment and particulate pollutants are re- pensive. Dry ponds require sediment removal much less fre-moved from water when they are allowed to settle to the quently because they accumulate less sediment per storm.bottom of the pond. Because water is present in dry ponds Both types of structures should be inspected on a regularfor relatively short periods of time, most of this sediment basis to ensure they are functioning correctly.remains suspended in the water released from the pond.However, wet ponds hold water for longer periods of time,allowing for greater settling of suspended sediments and non- Wet Ponds as Community Assetssoluble pollutants, thus improving water quality in water In the past in the Northeast, dry ponds have been builtbodies receiving this flow. In addition, aquatic plants present more frequently than wet ponds. This trend is beginning toin wet ponds are able to further improve water quality by change as citizen concern over water quality and availabil-using some of the soluble pollutants and incorporating them ity continues to escalate and land planners and engineersinto plant tissue. become aware of the multiple values and benefits associated with well-designed and landscaped wet ponds. Because wetGroundwater Recharge ponds are far superior to dry ponds in improving water qual- ity, providing wetland and wildlife habitat, and providing Groundwater recharge refers to water that infiltrates the recreational and educational opportunities, these pondssoil surface and percolates into the groundwater reservoir. Part should be built whenever they are feasible for available sites.of the water present in retention ponds infiltrates through the Wet ponds can be assets to a community because of thesebottom and sides of the pond into the groundwater reservoir. multiple benefits. In addition, they enhance the quality ofDetention ponds, on the other hand, usually allow less ground- life by providing attractive and tranquil refuges in the midstwater recharge because the water is only present a short pe- of an urban environment.riod of time before moving into a receiving body of water. Designing StormwaterWildlife Habitat and Structures for WildlifeRecreation Benefits The opportunity exists for creating wetland and wildlife Properly designed wet ponds can provide habitat for a habitat in conjunction with stormwater management. Designnumber of species of wildlife and native plants that are de- features that make a pond specifically attractive to wildlifependent on wetlands. Dry ponds, on the other hand, provide are described below. Each pond and site will be different,little opportunity for enhancing wildlife habitat. Wet ponds and not all of these recommendations will be possible forwill be used by various waterfowl species, furbearing ani- every pond. However, the recommendations are guidelinesmals, songbirds, and reptiles and amphibians. to assist planners in designing multi-purpose ponds that not Depending on their size and design, wet ponds can pro- only control stormwater and improve water quality, but govide a number of recreational opportunities including one step further by providing wetland and wildlife habitat.birdwatching, fishing, boating, and ice skating. Dry ponds Stormwater regulations vary from location to location anddo not typically provide such recreational values. should be consulted before developing a management plan. In addition, it is beneficial to consult with a wildlife biolo-Construction and gist for additional input on specific projects.Maintenance Costs Water depth and bank slope Construction costs are generally 30 to 60 percent higher To maximize wildlife habitat and pollutant removal, wetfor wet ponds than for dry ponds. However, many studies ponds should be shallow with gently sloping sides. In gen-have shown that homeowners are willing to pay more for eral, 25 to 50 percent of the water surface area should behouses near landscaped ponds, and developers are often able between two and three feet deep. The shallow water areasto make up this initial deficit. In addition, landscaped ponds provide habitat for tadpoles, small fish, and aquatic insectsprovide numerous other benefits that cannot be translated like dragonflies and mayflies. These in turn provide food fordirectly into dollar values, such as improved water quality waterfowl, wading birds such as great blue herons, and otherand wildlife habitat. 2
  3. 3. wildlife. Shallow areas are also necessary to establish aquatic will eventually develop vegetation, it will do so faster and be-plants that provide both food and cover for waterfowl and come an attractive pond with both aesthetic and wildlife valueother wildlife. A slope of 10:1 (1 inch elevation gain every when a landscape plan is developed and implemented.10 inches) along the edge will provide shallow water habitat The types of vegetation that can be established depend onwhere aquatic plants can be established. the water depth and also on how frequently the area is inun- Studies have shown that shallow ponds beneficial for dated with water. For landscaping purposes, Schueler (1987)wildlife are also better for improving water quality and are has divided stormwater ponds into six zones that relate to soilsafer for children. If one objective of the pond is to maintain moisture and the types of vegetation that can be establishedfish populations, part of the pond should be at least eight (Figure 1). The tables on pages 4-5 provide a representativefeet deep. list of plant species that can be planted in most zones.Shoreline Nest boxes The edge between the terrestrial environment and the Nest boxes along the edge of the pond and nesting plat-water is the shoreline. This edge can be an extremely pro- forms within the pond can be used to attract a variety ofductive habitat for prey species such as insects, frogs, and wildlife and will increase the visibility of wildlife to peoplecrayfish, which in turn attract a diversity of birds and mam- visiting the pond. Species that use nest boxes include themals. When possible, the length of shoreline should be maxi- eastern bluebird, house wren, tree swallow, and purple mar-mized. This can be done by building ponds with irregular tin. A pond near woods may also attract wood ducks. Canadainstead of circular shapes. geese, and mallards will nest on platforms in the pond, and In large ponds, irregular shorelines having many coves turtles and ducks will use loafing platforms. Nest boxes andenable pairs of birds to become visually isolated from one platforms can be built or purchased from local lawn and gar-another. That is, a pair of birds can set up a territory in one den stores or nature centers, or you can contact your localcove and not be seen by their neighbors in the next cove. county Extension office or the Kentucky Department of FishResearch has shown that for many species the number of and Wildlife Resources for plans to construct your own.individuals that will breed on a pond is greatly increasedwhen pairs are visually isolated from one another. Summary of Planning forMudflats, sandbars, and islands Stormwater Control Ponds Providing exposed mudflats or sandbars is one of the best A summary of planning and design guidelines for opti-ways of making a pond attractive to shorebirds, wading birds, mizing the value of constructed urban stormwater controland waterfowl. Shorebirds and wading birds feed in these ponds as wetland reserves for wildlife is presented below.nutrient-rich areas while the waterfowl use them for resting • Where possible, impoundments for stormwater controland loafing. Mudflats or sandbars are established and main- should retain water rather than merely detain it.tained by fluctuating water levels that deposit nutrients into • Pond design must meet applicable stormwater controlthe soil and keep permanent vegetation from becoming es- criteria, including legal requirements.tablished. Mudflats and sandbars will develop naturally in • Natural resources personnel, including biologists, shouldshallow ponds with gradually sloped sides. The sloped sides be consulted during the planning and design stages.will be underwater during periods of heavy rainfall and ex- • All potential pond locations should be evaluated to selectposed during dry periods. the most suitable site in relation to the developed area and Islands within the center of the pond provide a place for surroundings, and in recognition of physical, social, eco-waterfowl to nest where they are protected from predators nomic, and biologic factors.such as racoons or local dogs and cats. This is particularly • There should be an adequate drainage area to provide aimportant in suburban and urban areas where populations of dependable source of water for the intended year-round usethese predators are high. Even if the pond is small, try to of the pond, considering seepage and evaporation losses.establish at least one island. An island as small as 30 square • The soil on site must have sufficient bearing strength (atfeet will provide a nest site for a pair of ducks. These islands least 20 percent clay) to support the dam without excessiveshould be above the high water mark and should have sloped consolidation and be impermeable enough to hold water.sides so water will drain. Establishing grass on the island • The pond site should be located in an area where distur-will prevent erosion and provide nesting cover. bances to valuable existing wildlife habitat by construction activities will be avoided or minimized. • Impoundments with gently sloping sides (on the order ofLandscaping 10:1) are preferable to impoundments with steep slopes. Shrubs and trees along the edge of ponds and islands pro- Gently sloping sides will encourage the establishment ofvide nest sites, perching sites, and cover for a variety of wild- marsh vegetation. Vegetation will provide food and coverlife. Aquatic plants within the pond provide food and cover for for wildlife and help to enhance water quality. Impound-waterfowl and other wildlife. Although a completely barren pond 3
  4. 4. ments with gently sloping sides are also safer than steep- Water quality can be enhanced by a flow-through system sided ponds for children who might enter the impound- where water is continually flushed through the impound- ments, and gently sloping sides facilitate use by terrestrial ment. Islands should be gently sloping, and the tops should wildlife. be graded to provide good drainage. Appropriate vegeta-• Water depth should not exceed 2 ft. for 25 percent to 50 tive cover should be established to prevent erosion and percent of the water surface area, with approximately 50 provide bird nesting cover. Consideration should be given percent to 75 percent having a depth not less than 3 ½ ft. to including an overland flow area in the design of large• An emergent vegetation/open-water ratio of about 50:50 impoundments. should be maintained. • Impoundments should be designed with the capacity to• For larger impoundments (>1 acre), one or more small regulate water levels, including complete drainage, and islands should be constructed. The shape and position of with facilities for cleaning, if necessary. islands should be designed to help direct water flow within • Locating permanent-water impoundments near existing the impoundment. Water flow around and between islands wetlands generally will enhance the wildlife values of can help to oxygenate the water and prevent stagnation. impoundments.Plants for Stormwater Control Pond Vegetation Zones Every effort has been made to fit wetland plants into appropriate zones. However, many plants can be quite adaptable to avariety of zones and may spread or move after initial planting. The following woody species may not need to be seeded becausethey may invade naturally: red maple (Acer rubrum), silver maple (Acer saccharum), box elder (Acer negundo), green ash(Fraxinus pennsylvanica), sycamore (Platanus occidentalis), river birch (Betula niger), and cottonwood (Populus deltoides).Zone 1: Deep Water (permanent water 1 to 8 ft. Zone 2: Shallow Water (permanently wet ordeep: mostly 2 ft. to 3 ft. deep) semipermanently inundated up to 1 foot deep)Common Name Scientific Name Herbaceous Plant MaterialHerbaceous Plant Material Cooper Iris Iris fulvaDuckweed Lemna spp. Southern Blue Flag Iris Iris versicolorCoontail Ceratophyllum spp. Pickerel Weed Pontederia cordataWater Milfoil Myriophyllum spp. Sweet Flag Acorus calamusAmerican Lotus* Nelumbo lutea Arrowhead Sagittaria latifoliaSpadderdock* Nuphar advena Lizard’s Tail Saururus cernuusWhite Water Lily Nymphea odorata Spiderlily Hymenocallis occidentalis* These species are invasive and can cover the entire open Water Plantain Alisma subcordatumwater portion of a pond. To control the invasive nature of Creeping Primrose Ludwigia repensthese plants. grow them in containers. Marsh Millet Zizaniopsis miliacea Shrubs Buttonbush Cephalanthus occidentalis Swamp Privet Forestiera acuminata Swamp Haw Viburnum nudum Winterberry Ilex verticillata Common Alder Alnus serrulata Swamp Rose Rosa palustris Rose Mallow* Hibiscus moscheutos Swamp Mallow* Hibiscus militaris Trees Bald Cypress Taxodium distichum Water Tupelo Nyssa aquatica Water Hickory Carya aquatica Swamp White Oak Quercus bicolor Overcup Oak Quercus lyrata 4
  5. 5. Zone 3: Pond Shoreline (water tolerant but can be Zone 4: Riparian Fringe (must be able to tolerateexposed for extended dry periods). both wet and dry conditions)Common Name Scientific Name Common Name Scientific NameHerbaceous Plant Material Herbaceous Plant MaterialMarsh Violet Viola cucullata GrassesTickseed Sunflower Bidens spp. Eastern Gamagrass Tripsacum dactyloidesCardinal Flower Lobelia cardinalis Prairie Cordgrass Spartina pectinataGreat Blue Lobelia Lobelia siphilitica Switchgrass Panicum virgatumMonkey Flower Mimulus ringens or (alatus) Big Bluestem Andropogon gerardiiJoe-pye-weed Eupatorium fistulosum or Wild Rye Elymus virginicus (maculatum) or (purpureum) WildflowersMeadowbeauty Rhexia verginica New England Aster Aster novae-angliaeRed Milkweed Asclepias incarnata Dense Blazingstar Liatris spicataSoapwort Gentian Gentian saponaria Sweet Black-eyed Susan Rudbeckia subtomentosaJewelweeds Impatiens pallida or Branched Coneflower Rudbeckia triloba (capensis) Golden Alexanders Zizia aureaTurtlehead Chelone glabra Ironweed Veronia altissima orBoneset Eupatorium perfoliatum (noveboracensis)Cinnamon Fern Osmunda cinnamomea False Dragonhead Physostegia virginianaRoyal Fern Osmunda regalis Shrubs (shrubs listed in Zone 3 will work in addition to theHorsetail Equisitum spp. following species)Cattail* Typha latifolia Smooth Sumac Rhus glabraSoft Rush Juncus effusus Blackhaw Viburnum prunifoliumFrank’s Sedge Carex frankii Spicebush Lindera benzoinFox Sedge Carex vulpinoidea False Indigo Amorpha fruiticosaSoftstem Bulrush Scripus atrovirens Trees (all the trees listed in Zone 3 will work in addition toDark Green Rulrush Scripus validus the following species)Burreed Sparganium americanum Northern Red Oak Quercus rubraSpikerushes Elocharis spp. Shumard Oak Quercus shumardiiCutgrass Leersia spp. Black Walnut Juglans nigraShrubs Red Elm Ulmus rubraSweetshrub Clethra alnifolia or Yellow Poplar Liriodendron tulipifera (acuminata) White Ash Fraxinus americanaAmerican Elderberry Sambucus canadensis American Basswood Tilia americanaGray Dogwood Cornus racemosa American Hornbeam Carpinus carolinianaSilky Dogwood Cornus amomum Eastern Hophornbeam Ostrya virginianaStiff Dogwood Cornus foemina Buckeye Aesculus glabraArrow-wood Viburnum dentatum Downy Hawthorn Crataegus mollisWithe-rod Viburnum cassinoidesDeciduous Holly Ilex deciduaSteeplebush Spirea tomentosaTreesPin Oak Quercus palustris Zone 5: Floodplain Terrrace and Zone 6: Upland SlopesSwamp Chestnut Oak Quercus michauxiiCherrybark Oak Quercus pagoda For woody plants suitable for Zones 5 and 6 (upland sites),Bur Oak Quercus macrocarpa ask your county Extension office for a copy of the publication,Willow Oak Quercus phellos Trees, Shrubs, and Vines That Attract Wildlife (FOR-68).Swamp White Oak Quercus bicolorSugarberry Celtis laevigataSweetgum Liquidambar styracifluaShellbark Hickory Carya laciniosaBlackgum Nyssa sylvaticaAmerican Elm Ulmus americana 5
  6. 6. No trees on embankment. ZONE 6. ZONE 5. UPLAND SLOPES FLOODPLAIN TERRACE Seldom or never inundated; ZONE 4. Infrequently inundated; moist to dry soils. ZONE 3. RIPARIAN moist soils. POND FRINGE ZONE 2. Periodically ZONE 1. SHALLOW SHORELINE regularly inundated DEEP WATER AREAS WATER area; wet 1-8 feet deep; AREAS inundated area. soils. submerged aquatic 6-12 plants. inches deep; emergent aquatic plants. Figure 1. Landscaping zones in stormwater areas. Adapted from Wittans and Weiss, 1985, and Schueler, 1987.Zone 1: Deep Water Areas Zone 4: Riparian Fringe Area This is the wettest zone; these areas are permanently un- Plants in this zone must be able to tolerate both wet andder one to eight feet of water. Plants in this zone require dry soil conditions and periodic inundation. Potential tree spe-permanently saturated soils and are predominated by cies include black willow, green ash, red maple, and sycamore.submergent aquatics (wild celery, coontail, water milfoil, sagopondweed) and floating plants such as duckweed, water lo-tus, spadderdock, waterlily, and eelgrass. Zone 5: Floodplain Terrace This zone includes most of the pond embankments. Trees that grow in this zone prefer moist soil but can tolerate in-Zone 2: Shallow Water Areas frequent inundation. These species include silky dogwood, This zone is permanently wet with an average water depth elderberry, and spicebush. When landscaping around theof less than one foot or semi-permanently inundated. Eco- pond, avoid planting trees and shrubs on the embankment orlogical communities typified by this zone include bottom- along the dam because their roots can be destructive to theland hardwood forests, wet prairies and marshes, seeps, ponds dam. In general, a pond designed for waterfowl has onlyand sloughs, and the margins of lakes. Plants adapted to this about 50 percent of this zone planted with trees and shrubs.zone prefer continuously wet soils and tolerate extendedperiods of flooding or inundation. Examples of plants wouldinclude cattails, rushes, burreed, sweet flag, copper iris, Zone 6: Upland Slopessouthern blue flag iris, and cinnamon fern. This area is seldom inundated with water. Trees that can be planted here include chokeberry, elderberry, and dogwood. For woody plants suitable for Zones 5 and 6 (upland sites), ask yourZone 3: Pond Shoreline county Extension office for a copy of the publication, Trees, Plants in this zone must be tolerant of inundation during Shrubs, and Vines That Attract Wildlife (FOR-68).storms and exposure during dry periods. Vegetation that canbe established here includes sedges, buttonbush, and cattail.Parts of the shoreline should be kept free of vegetation andmaintained as mudflats or sandbars.Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability, or national origin. Issued in furtherance ofCooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, C. Oran Little, Director of Cooperative Extension Service, Universityof Kentucky College of Agriculture, Lexington, and Kentucky State University, Frankfort. Copyright © 1998 for materials developed by the University of Kentucky Cooperative ExtensionService. This publication may be reproduced in portions or its entirety for educational or nonprofit purposes only. Permitted users shall give credit to the author(s) and include thiscopyright notice. Publications are also available on the World Wide Web at: http://www.ca.uky.edu. Issued 11-98, 1000 copies.

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