4 Surface Water Management
Whether natural or manmade, surface water in the form of lakes, ponds, and streams has long been associated with golf courses. Natural lakes and ponds are usually associated with existing water sources, such as wetland areas. Irrigation impoundments (lakes, ponds, and constructed wetlands) can be incorporated into the design of a course and used both to manage stormwater and to function as a source for irrigation. Overall, surface water management incorporates not only the information contained in this chapter, but many of the issues discussed throughout this document, including:
- design considerations such as the use of vegetated buffers
- fertilization strategies near surface waters
- pesticide usage
- water quality monitoring
When golf courses are designed and built, their drainage capability concept is guided by an average rainfall event of a given frequency. For example, a golf course drainage system is typically designed to retain a two- or five-year rain event, reasonably draining the precipitation in a matter of hours, with excess water that has not infiltrated into the ground retained temporarily until it leaves the property. In some instances, golf courses are mandated to handle a 20-, 50-, or 100-year rain event, which means the golf course must retain more water, potentially for a longer period of time. This ability to retain large amounts of water requires accurate engineering and extensive construction to prevent physical or financial damage to the facility. Many BMPs prolong the retention process as long as practical, retaining as much of the stormwater in surface or underground storage as is reasonable, and may even improve the quality of water leaving the property.
Except for temporary retention ponds, most aquatic areas require their own management plan and regular attention. Important components of aquatic maintenance include managing aquatic habitats, such as the aquatic algae and plant growth and dissolved oxygen; reducing or preventing nutrient and sediment enrichment especially through the use of vegetated buffers; and ensuring adequate dissolved oxygen levels to sustain aquatic life.
4.1 Regulatory Considerations
Course owners and superintendents should thoroughly investigate all regulatory requirements that apply to the golf facility to protect water quality and to manage stormwater. DNREC sets standards for the level of protection afforded to each body of surface water in the state (see State of Delaware Water Quality Standards, 2014). Water quality standards protect and enhance surface water quality, protect public health and welfare, protect aquatic resources, and serve the purposes of the federal Clean Water Act (CWA) and all its amendments. In practice, Delaware’s water quality standards form the basis for state programs that control the amount of pollutants entering waters from such sources as industrial plants, sewage treatment plants, storm sewers, and runoff from urban and rural areas. For more information on state programs related to surface water quality, see DNREC’s Surface Water Quality Standards. Water quality information can be found in DNREC’s Water Quality Monitoring Network Data Portal.
Surface waterbodies not meeting surface water quality standards may be subject to pollution limits, also known as the Total Maximum Daily Load (TMDL). TMDLs establish the maximum amount of an impairing substance or stressor that a waterbody can assimilate and still meet water quality standards and allocates the pollutant load among pollution contributors. TMDLs are a tool for implementing state water quality standards and are based on the relationship between pollution sources and in-stream water quality conditions. Detailed information on Delaware’s TMDLs can be found in the state’s 2016 Combined Watershed Assessment Report (305(b)) and Determination for the Clean Water Act Section 303(d) List of Waters Needing TMDLs.
TMDLs have been set to fully restore the health of the Chesapeake Bay. The Environmental Protection Agency (EPA) established pollution load limits to restrict three major pollutants in the Bay watershed: nitrogen and phosphorus (nutrients) and sediment (soil). These load limits, which set clear goals for reducing excess pollution, are science-based estimates of the amount of each substance the Chesapeake Bay and its tributaries can receive and still meet standards for clean, healthy water. The goals, or pollution reduction targets, require the seven jurisdictions in the Chesapeake Bay watershed (Maryland, Virginia, Pennsylvania, Delaware, West Virginia, New York and the District of Columbia) to reduce their nutrient and sediment loadings to the Bay until these protective limits are met, within a specific time frame.
In response to these TMDLs, the seven Bay jurisdictions created individual Watershed Implementation Plans (WIP), or restoration blueprints, that detail specific actions each would take to meet their pollution reduction goals by 2025. These WIPs have been developed in three phases, with each successive WIP increasing the level of detail of load goals and actions to achieve those goals. Delaware’s Phase II WIP was published in 2012; the Phase III WIP is due to EPA in 2019. The blueprints guide local and state Bay restoration efforts through the next decade and beyond.
Delaware has developed comprehensive programs for stormwater management and for erosion and sediment control that are designed to reduce the adverse impacts of development on stormwater runoff. This program addresses both the temporary and permanent impacts associated with development activities. New development projects must follow regulatory requirements that allow runoff to infiltrate through the soil and recharge groundwater supplies. Post construction stormwater management practices must be designed, constructed and maintained in accordance with Sections 11.0 and 12.0 of the 7 DE Admin Code 5101 Delaware Sediment and Stormwater Regulations. The regulatory guidance document “Standards and Specifications for Post Construction Stormwater Management BMPs” offers additional guidance in the design, construction and maintenance of stormwater BMPs.
4.2 Stormwater Management
The control of stormwater on a golf course is more than just preventing the flooding of the clubhouse, maintenance sites, and play areas. Proper management of stormwater controls the amount and rate of water leaving the course, controls erosion and sedimentation, stores irrigation water, removes waterborne pollutants, enhances wildlife habitat, and addresses aesthetic and playability concerns. Stormwater runoff (also called surface runoff) is the conveying force behind what is called non-point source pollution. Non-point source pollution is caused by water moving over and through the ground, picking up and carrying away natural and human-made pollutants, and finally depositing them into surface waters (lakes, rivers, wetlands, coastal waters) and groundwater. On golf courses, pollutants that might be found in surface runoff include, but are not limited to, pesticides, fertilizers, sediment, and petroleum.
Treating stormwater to avoid impacts to water quality is best accomplished by a treatment train approach in which water is conveyed from one treatment to another by conveyances that themselves contribute to the treatment. These treatments include source controls, structural controls, and non-structural controls. Source controls are the first car of the BMP treatment train. They help prevent the generation of stormwater runoff or the introduction of pollutants into stormwater runoff. The most effective method of stormwater treatment is to prevent or preclude the possibility of movement of sediment, nutrients, or pesticides in runoff.
The next car in the treatment system is often structural controls, which are design and engineering features of the course created to remove, filter, detain, or reroute potential contaminants carried in surface runoff (Figures 11 and 12). Examples of structural BMPs include infiltration basins, stormwater ponds, constructed wetlands, and filters to address water quality, water recharge, and stream channel protection. Non-structural controls mimic natural hydrology and minimize the generation of excess stormwater and include vegetated systems. Vegetated systems such as stream buffers act as natural biofilters, reducing stormwater flow, removing sediments from surface water runoff, and preventing nutrient and pesticide discharge in runoff from reaching surface waters (Figure 13). The treatment train approach combines these controls, as in the following example: Stormwater can be directed across vegetated filter strips (such as turfgrass), through a swale into a wet detention pond, and then out through another swale to a constructed wetland system.
During any construction or redesign activity, proper erosion and sedimentation control must be followed (as discussed in the “Planning, Design, and Construction” chapter) to ensure that stormwater runoff does not impact water quality. Properly designed golf courses capture rain and runoff in water hazards and stormwater ponds, providing most or all of the supplemental water necessary under normal conditions, though backup sources may be needed during drought conditions.
Re-establishment of natural water systems helps mitigate flooding and control stormwater. Therefore, high sediment and nutrient loads should be addressed, as well as vertical and lateral stream migration, which causes unstable banks, flooding, and reductions in groundwater recharge. Land use decisions and engineering standards must be based on the latest research science available.
The biological activity of plants, fish, animals, insects, and especially bacteria and fungi in a healthy, diverse wetland is the recycling factory of our ecosystem. While wetlands do pose a special concern, their mere presence is not incompatible with environmentally sound golf courses. With care in design and management, many golf holes have been threaded through sensitive areas. When incorporated into a golf course design, wetlands should be maintained as preserves and separated from managed turf areas with native vegetation or structural buffers. In addition, constructed or disturbed wetlands can be designed and permitted as an integral part of the stormwater management system.
4.5 Lakes and Ponds
Most golf courses plan their lakes and water hazards to be a part of the stormwater control and treatment system. However, natural waters of the state cannot be considered treatment systems and must be protected. Lakes and ponds may also be used as a source of irrigation water. Therefore, it is important to consider these functions when designing and constructing the ponds. Peninsular projections and long, narrow fingers may prevent mixing. Ponds that are too shallow may reach high temperatures, leading to low oxygen levels and promoting algal growth and excess sedimentation.
The management of lakes and ponds should include a clear statement of goals and priorities to guide the development of the BMPs necessary to meet those goals. Some of the challenges facing superintendents in maintaining the quality of golf course ponds are as follows:
- low dissolved oxygen (DO) levels
- changes in plant populations
- nuisance vegetation
- maintenance of littoral shelves
- vegetation on the lakeshore
Nutrient enrichment from nitrogen, phosphorus, and sediments in surface water runoff can increase the growth of aquatic plants, algae, and bacteria in ponds. Therefore, one of the most important BMPs is to maintain a riparian buffer around surfaces waters to filter the nutrients and sediments in runoff. In fact, the DNREC calls vegetated buffers around a lake or pond “the single, most valuable management practice.” The DNREC recommends a 15- to 20-foot wide area around waterbodies that is left unmowed or mowed only once or twice a year so that grasses and plants grow knee-high (Figure 13). In addition to allowing silt and nutrients to drop before reaching surface waters, these buffer strips also discourage geese from taking up residence, as they prefer shorter grassy areas. For more information, see the DNREC’s Best Management Practices for Small Ponds.
Delaware’s nutrient management regulations specify that fertilizers cannot be applied within 15 feet of waterways. This setback is reduced to 10 feet if a drop spreader, rotary spreader with deflector, or targeted spray liquid is used to apply fertilizer.
4.5.1 Dissolved Oxygen
DO is the amount of oxygen that is present in water and is measured in milligrams per liter (mg/L). Adequate DO levels are required to sustain life in aquatic organisms and vary by species, the organism’s life stage, and water temperature. The amount of DO that water can hold depends on the physical conditions of the body of water (water temperature, rate of flow, oxygen mixing, etc.) and photosynthetic activity. Colder water has higher DO levels than warmer water. DO levels will also differ by time of day and by season as water temperatures fluctuate. Similarly, a difference in DO levels may be seen at different depths in deeper surface waters if the water stratifies into thermal layers. Aerators can be used to increase DO levels in shallow water bodies (Figure 14).
Flow rates influence DO levels. For example, fast-flowing streams hold more oxygen than impounded water. Photosynthetic activity also influences DO. As aquatic plants and algae photosynthesize during the day, they release oxygen. At night, photosynthesis slows down considerably or even stops, and algae and plants pull oxygen from the water. In impoundments with excessive plant and algae growth, several cloudy days in a row can increase the potential for fish kills during warm weather. Therefore, preventing excessive aquatic growth by preventing nutrient enrichment will help maintain DO levels.
4.5.2 Aquatic Algae and Plants
Phytoplankton, or algae, give water its green appearance and provide the base for the food chain in ponds. Tiny animals called zooplankton use phytoplankton as a food source. Large aquatic plants (aquatic macrophytes) can grow rooted to the bottom and supported by the water (submersed plants), rooted to the bottom or shoreline and extended above the water surface (emersed plants), rooted to the bottom with their leaves floating on the water surface (floating-leaved plants), or free-floating on the water surface (floating plants).
These different types of aquatic macrophytes can have different functions that protect water quality. Aquatic plants growing on a littoral shelf may help protect receiving waters from the pollutants present in surface water runoff. In open areas, floating-leaved and free-floating plants suppress phytoplankton because they absorb nutrients from the pond water and create shade. For more information on managing aquatic plants and algae in ponds in Delaware, see the DNREC Division of Fish and Wildlife web page about Aquatic Plants and Herbicides. See Recommended Herbaceous Plants for Stormwater Management Ponds in Delaware for Delaware-specific native aquatic plant recommendations.
Use of grass carp for aquatic weed control is governed by DNREC policy and limited to Ctenopharyngodon idella, a functionally sterile form.
The deposits of fecal matter by resident and migrating waterfowl (such as Canada geese) can substantially impact water quality through nutrient enrichment. On golf courses, shallow ponds with significant populations of waterfowl are most likely to be affected. In addition, large numbers of Canada geese can erode shorelines and thin the grass cover on greens and fairways, contributing to the potential for erosion. Once geese have become established, efforts to control them have met with mixed success. Loud sounds, dogs, and hunting have been tried in order to deter them. USDA goose round-ups and depredation permits can also be acquired to manage goose populations. However, many of these efforts do not lend themselves to golf courses, especially in more urban areas. For more information, see also Canada Goose Management Series: Harassment from Rutgers University.
4.6 Water Management Best Management Practices
Stormwater Management Best Management Practices
- Design stormwater treatment trains.
- Install berms and vegetated swales to capture pollutants and sediments from runoff before it enters irrigation storage ponds or other surface waters.
- Implement no- or low-maintenance vegetated buffer strips around surface waters.
- Utilize vegetated filter strips in conjunction with water filtration basins.
- Eliminate or minimize directly connected impervious areas.
- Use depressed landscape islands in parking lots to catch and filter water and allow for infiltration. When hard rains occur, an elevated stormwater drain inlet allows the island to hold the treatment volume and settle out sediment, while allowing the overflow to drain away.
- When possible, maximize the use of pervious pavements, such as brick or concrete pavers separated by sand and plants.
Floodplains Best Management Practices
- Install stream buffers to restore natural water flows and flooding controls.
- Install buffers in play areas to stabilize and restore natural areas that will attract wildlife species.
- Install detention basins to store water and reduce flooding at peak flows.
Wetlands Best Management Practices
- Maintain appropriate silt fencing on projects upstream to prevent erosion and sedimentation.
- Natural waters cannot be considered treatment systems and must be protected. (Natural waters do not include treatment wetlands.)
- Establish a low- to no-maintenance level within a 75-foot buffer along nontidal and tidal wetlands.
- Establish and maintain a 100-foot riparian buffer around wetlands, springs, and spring runs.
Lake and Pond Best Management Practices
- Maintain a 15-20 foot unmowed, vegetated buffer strip (riparian buffer) to filter the nutrients and sediment in runoff. Leave unmowed or mow only once or twice a year so that grasses and plants grow knee-high.
- If mowing near a pond or lake, collect clippings or direct them to upland areas so they do not increase nutrient loading to waterbodies.
- Maintain the required setback distance when applying fertilizers near waterways.
- Encourage clumps of native emergent vegetation at the shoreline.
- Maintain water flow through lakes if they are interconnected.
- Establish wetlands where water enters lakes to slow water flow and trap sediments.
- Maintain appropriate erosion and sedimentation controls on projects upstream to prevent sedimentation and nutrient enrichment to waterbodies.
- Dredge or remove sediment before it becomes a problem.
Dissolved Oxygen Best Management Practices
- Establish DO thresholds to prevent fish kills, which occur at levels of 2-3 mg/L.
- Reduce stress on fish by keeping DO levels above 5 mg/L.
- Manipulate water levels to prevent low levels that result in warmer temperatures and lowered DO levels.
- Use artificial aeration (diffusers) if needed to maintain adequate DO.
Aquatic Algae and Plants Best Management Practices
- In ponds with littoral plantings, problem plants should be selectively controlled without damaging littoral shelves.
- Encourage clumps of native emergent vegetation at the shoreline.
- A comprehensive management plan should include strategies to control the growth of nuisance vegetation that can negatively affect a pond’s water quality and treatment capacity.
- Frequently remove filamentous algae by hand and/or frequently apply algaecide to small areas of algae (spot treatment).
- Use algaecides containing hydrogen peroxide instead of copper or endothall to reduce the risk of oxygen depletion.
- To control excessive aquatic plant growth, mechanical methods can be used that include the placement of barriers such as plastic mesh to block sunlight penetration into the pond, and physically pulling, raking, and cutting weeds. Aquatic herbicides, if used to control excessive aquatic plant growth, require a permit.