| 04/09/2008 |
| Remedies to Protect Water Quality at Ada Hayden Heritage Park |
| By: Erv Klaas , Story County Soil and Water Conservation District |
|
The city of Ames has invested in excess of $7.5 million of public funds in Ada Hayden Heritage Park. It is recognized as a major asset of our city's park system and is now heavily used for a wide variety of outdoor recreation activities. It also provides excellent habitat for a variety of wildlife. The lake, and perhaps the aquifer beneath it, is an alternative drinking water source. The lake is the primary attraction in this park because water quality is among the best in the state (comparable to West Lake Okoboji). Therefore we need to take whatever measures we can to protect the lake and the water in it. Cleaning it up after it has become polluted with nutrients and algae growth will be very expensive if not impossible. My first choice of a remedy would be for all undeveloped land bordering the park to be put into public ownership and planted in perennial vegetation such as native prairie. Such action is not unusual, even in Iowa, to protect drinking water sources. But, who believes this is a politically viable idea? Denying developers the right to develop their land (which I doubt can be done under current laws, i.e. county zoning laws, county/city fringe plan) would probably mean leaving the land in agriculture production. This would be undesirable because the farmers who are renting the land for row crop production are not using adequate conservation practices and silt and nutrients are flowing into the park's constructed wetlands and lake unabated. Soon after I was elected a Commissioner for the Story County Soil and Water Conservation District I wrote a successful grant proposal to the state of Iowa. The District received more than $200,000 to implement conservation practices in the Ada Hayden Heritage Park watershed. The district used most of this money to help farmers in the watershed develop conservation plans, implement nutrient management plans, restore wetlands and other conservation practices. With one exception, these farms were north of 190th Street. The one exception was the farm immediately adjacent to the north side of the park. Cost share funds were used to install a soil stabilization structure and grass waterways. Recently, this farm was sold to a local developer. Another developer, who owned land west of the park, refused our offer to share the cost of conservation practices on his land. This tract, which is presently being proposed for development in the county, has one of the primary tributaries carrying polluted water into the park and includes some of the most erodible soils in the watershed. We offered cost-share funds to install buffer strips, soil stabilization structures, grass waterways, terraces, and a large sediment basin. When the Land Use Policy Plan (LUPP) for Ames was adopted in 1997, land to the north of Top-o-Hollow Road and Bloomington Road was not included in the 30-year plan as a preferred area of growth because the city determined that infrastructure (sewer lines, new fire station, streets, etc.) costs would be high compared to other areas to the south and west of the city. A second economic study conducted by the city's planning department a few years later at the request of developers reaffirmed the earlier study. A couple of years later the city allowed new residential subdivisions to be built north of Bloomington Road when developers complained that land in the southwest growth area was unavailable because of unwilling sellers, mainly Iowa State University. This led to the development of North Ridge Heights and Bloomington Heights. Developers agreed to install some of the necessary infrastructure at their own expense. In 1999, at the request of Hubbell Development Corporation of Des Moines, the city changed the LUPP to designate the area around the former Hallett's Quarry from industrial to residential development. A few months later, responding to public opinion and concerns about the use of water in the quarry as a secondary drinking water source, the city turned down Hubbell's request for annexation that essentially killed the development proposal. As a compromise, the city allowed Hubbell to develop approximately 25 acres of their land on the south side of the quarry. This subdivision is now known as The Reserve. In 2002, with the help of a successful passage of a bond issue and a state grant, the city purchased the land around Hallett's Quarry and created Ada Hayden Heritage Park. A causeway was removed to create a single large 130-acre lake from the original two gravel pits. A water control device was installed at the outlet to the lake to regulate water levels and prevent flooding from the Skunk River. The lake shoreline was graded, sloped, and armored with rip rap at the water line to prevent wind erosion. Trails, parking lots, fishing docks, and a boat access were installed. Three wetland complexes were constructed to intercept and treat surface water runoff from three major tributaries. The park has received intensive use since it was opened in 2004. Much of the southern half of the Hayden Park watershed has been developed as urban residential subdivisions within the city limits of Ames (The Reserve, Stonebrook, Bloomington Heights and part of Northridge Heights). Developers now own all the undeveloped land bordering the park on the north and west including the Oaks Golf Course. All of this land is outside the Ames city limits but is within the 2-mile urban fringe. In 2007, Story County Supervisors approved the rezoning of about 250 acres of land adjoining the west boundary of the park from agriculture to rural residential. A local developer has submitted a plan for a residential subdivision (Rose Prairie) of about 300 homes on this re-zoned property. The proposed development is designed as a low-impact development. Such developments are designed as small-lot subdivisions with 30-40% open space that is used to treat and infiltrate storm water. A low-impact development on this site will probably be an improvement in storm water management over current farming practices. Retention and infiltration of storm water into the ground is generally thought to be preferable to putting it directly into storm sewers and piping it directly to streams and rivers. However, if new home owners use fertilizers containing phosphorus, surface water runoff infiltrated into the ground could cause further contamination of ground water that eventually may find its way into Hayden Park Lake. Phosphorus and nitrogen are the two major nutrients that are of concern in protecting water quality in Hayden Park Lake. For unknown reasons, the constructed wetlands are not working as well as expected and phosphorus levels continue to slowly increase in the park's lake according to Dr. John Downing, ISU aquatic ecologist, who has been monitoring the lake's water since 2002. Dr. Downing believes that nutrient levels are already too high and nutrient inputs need to be reduced. Phosphorus levels are at the point where significant blooms of algae and cyanobacteria could impair the lake's water quality. Protection of existing water quality is much cheaper than cleaning it up later. Who is going to pay the bill when this lake is added to the state's impaired water list? In 2007, a semi-annual report of the Ames Aquifer Project was submitted to the city by ISU hydrogeologist Dr. Bill Simpkins. According to his report, shallow groundwater immediately adjacent to the north and west sides of Ada Hayden Lake contains relatively high levels (up to 300 ppb) of phosphorus (total P and SRP). His research, as well as a recent model of the lake by one of his graduate students, confirms that ground water in this part of the watershed moves slowly toward Hayden Park Lake. Groundwater containing high phosphorus concentrations is less than 10 years old and probably less than 5 years old, suggesting the phosphorus is coming from a nearby source. This means that ground water cannot be counted on as a dilution source in the lake, so nutrient levels in surface flows need to come down. The lake also provides a source of phosphorus to groundwater on the down gradient (Hwy 69) side of the lake. Thus, maintaining the health and water quality of the lake has implications for the larger Ames aquifer. If the proposed Rose Prairie development is allowed to go forward without connecting to the city's sanitary sewer lines, the developers will need to treat sanitary waste on site with some kind of centralized septic system. Septic systems are designed to remove solids from the waste water through settling and bacterial decomposition. The effluent from a septic system contains nutrients (phosphorus and nitrogen), bacteria, and possibly other contaminants, and is infiltrated into the ground through a system of perforated pipes called a leach field. The nutrient laden water eventually reaches groundwater. Thus, there is a potential for additional phosphorus to be added to the already contaminated groundwater that we know will eventually reach the park's lake. Polluted groundwater takes decades or centuries to fix and costs a lot. Because the land around Hayden Park is in the 2-mile fringe area, the city can require developers to take extraordinary measures to protect the waters of Hayden Park What these measures will be are not clear at this time. Remedies to protect water quality at Ada Hayden Heritage Park There are several remedies for the city that would protect the lake's water quality and allow development to proceed. A new comprehensive watershed protection plan should be developed that would include the following: 1. Change the LUPP designation and annex the land around the park south of 190th Street. 2. Install sanitary sewers that would transport sanitary waste to the city's municipal treatment plant. 3. Write new zoning codes for low-impact developments and impose a zoning overlay that would require low-impact development on all land within the Hayden Park Watershed. 4. Require developers to install groundwater monitoring wells for all new unsewered subdivisions. And, require developers to post bonds and guarantees large enough to cover water quality remediation, should it be shown that their development is responsible for degradation of water quality of surface or groundwater. 5. Initiate an aggressive education campaign to strongly encourage all property owners including golf courses and new and existing residences to use fertilizers containing zero phosphorus and minimize nitrogen and pesticide use. 6. Continue to monitor surface and ground water flows in the watershed and take corrective action when and where needed to protect water quality in Hayden Park and beyond. 7. Improve the nutrient removing functions of the constructed wetlands. 8. Request the Story County Soil and Water District to continue to work with agriculture producers in the watershed to implement conservation plans that will minimize nutrient fertilizer application and implement conservation practices to retain and treat surface water runoff. 9. Assist the owners of the equestrian center on 190th Street to implement manure management practices that will eliminate or significantly reduce nutrient inputs and retain and treat storm water runoff from their facility.
|