Threats to Water Quality Posed by the Proposed PGA Village Development
Vulnerable Land
According to the USGS, the proposed development is located over some of the most vulnerable[1] recharge zone land in Bexar County[2].
Contamination Likely
Few, if any, groundwater hydrologists would claim that contaminants (pesticides, fertilizers, hazardous constituents in treated sewage) from the development will not reach the Edwards Aquifer. The question is - will the amount of contaminants that reach the aquifer be significant or insignificant.
Pesticides in Aquifer
In 2000 the USGS published a study of water quality in south-central Texas[3]. Thirty of 31 Edwards Aquifer Recharge Zone wells sampled in Bexar County contained low concentrations of at least one pesticide[4] (concentrations were well below the standard set to protect human health). Some of the pesticides found are commonly used on golf courses[5]. Of course, this does not mean they came from golf courses. Unfortunately, no rigorous studies of the effect of golf courses on water quality in Bexar County have been performed.
Golf Courses and Pesticide Contamination
Studies in other parts of the US have established a clear link between golf courses and pesticides in groundwater[6]:
- Cape Cod Study - Pesticides found in groundwater at all four courses studied. Found in 9 of 12 monitor wells[7].
- Florida Study - Pesticides found in groundwater at 7 of 9 courses studied. Found in 52% of groundwater samples[8].
Contaminant Loads - Golf Courses vs. Residential
The developer claims that the proposed development will result in less pollution than a residential development. Although little information is available concerning the relative affects of golf courses and residential areas on water quality, a study done in Austin indicates that, on the whole, golf courses have a greater affect on water quality than low density (24% impervious cover) residential developments[11]. The study also concluded that both golf courses and residential developments have substantially greater affects on water quality than rural areas.
Developer Calculation of Impervious Cover
In the Water Pollution Abatement Plan[12] the developer claims that the single family residential developments at the proposed PGA Village will have approximately 16% impervious cover. This figure was calculated by including all the proposed open space. However, most of the open space (approximately 850 of 1100 acres = 77%) is in the Cibolo Creek watershed, while most of the single family residential development (approximately 375 of 420 acres = 89%) is in the Salado Creek watershed.
Water in the Cibolo watershed does not mix with water in the Salado watershed until the Cibolo joins the San Antonio River in Karns County, approximately 60 miles south of the proposed development. Thus, there is no water quality related reason for including most of the open space in the calculation of percent impervious cover.
Calculating the percent impervious cover of the single family residential development without the open space results in a value of 40%[13].
REFERENCES
Briggs S. A., and Rachel Carson Council, Inc., 1992, Basic Guide to Pesticides: Their Characteristics and Hazards.
City of Austin, 1997, The Barton Creek Report, Barton Creek Canyons Study: 1993 - 1995, April 1997.
Cohen, S., S. Nickerson, R. Maxey, A. Dupuy and J. Senita. 1990. "A Groundwater Monitoring Study for Pesticides and Nitrates Associated With Golf Courses on Cape Cod." Groundwater Monitoring Review. Winter 1990:160-173.
National Science and Technology Council, 1997, Endocrine Disruptors Research Initiative Fact Sheet, last modified on 03 March, 1997.
Pape-Dawson Engineers, Inc., 2001, Cibolo Canyon Resort Community Water Pollution Abatement Plan, December 2001.
Swancar, Amy, 1996, Water Quality, Pesticide Occurrence, and Effects of Irrigation With Reclaimed Water at Golf Courses in Florida: USGS Water-Resources Investigations Report 95-4250, 86 p.
U. S. Geological Survey, 1998, Pesticides Used on and Detected in Ground Water Beneath Golf Courses.
U. S. Geological Survey, 2000a, Vulnerability of Ground Water to Contamination, Edwards Aquifer Recharge Zone, Bexar County, Texas, 1998, USGS Water-Resources Investigations Report 00-4149.
U. S. Geological Survey, 2000b, Water Quality in South-Central Texas, National Water-Quality Assessment Program (NAWQA), USGS Circular 1212.
U. S. Geological Survey, 2001, National Reconnaissance of Emerging Contaminants in the Nation's Water Resources, last modified on 09 Jul 2001.
Wren, A., 2001, Occurrence and Fate of Endocrine Disruptors in Onsite Wastewater Systems, Colorado School of Mines, August 2001.
[1] Vulnerable with respect to groundwater contamination.
[2] U. S. Geological Survey, 2000a.
[3] U. S. Geological Survey, 2000b.
[4] U. S. Geological Survey, 2000b, figure 10.
[5] Briggs and RCC, 1992; and U. S. Geological Survey, 2000b, page 27.
[6] USGS, 1998; Swancar, 1996; Cohen, et al., 1990.
[7] Cohen, et al., 1990.
[8] Swancar, 1996.
[9] U. S. Geological Survey, 2001, and Wren, 2001.
[10] National Science and Technology Council, 1997.
[11] City of Austin, 1997.
[12] Pape-Dawson Engineers, Inc., 2001.
[13] Figure based on total single family residential (420 acres, 231 impervious), road (85 acres, 55.25 impervious), and floodplain (210 acres) = [231+55.25]/[410+85+210] = 0.40.
