Septic tanks, on-site wastewater treatment, well water, nitrate, longevity
Avon Lake, a rural-residential subdivision located southeast of Des Moines, has mostly summer cabins around a remnant gravel quarry. Surface material in the area is sand. Each of the homes has a shallow sand-point well for a water supply and a septic system for sewage treatment. Septic systems were examined for evidence of failure, house-to-house surveys were performed, and well water samples were taken. Fifty percent of the septic systems have been operating satisfactorily for more than 20 years. Only one of 68 well water samples contained fecal coliform bacteria. Thirty-six samples exceeded the nitrate standard, the highest being 25.6mg/1 N. Nitrate concentration seemed to change in space but not with well age. Nitrogen loadings from cropland, septic systems, and animals were also estimated; they ranged from 40-120 lb/acre (45-135 kg/ha) for cropland, 35 lb/acre (39 kg/ha) for septic systems, and 13 lb/acre (15 kg/ha) for dogs. All three of these could be important sources of nitrogen to the groundwater.
Proceedings of the Iowa Academy of Science
©1982 Iowa Academy of Science, Inc.
Mancl, Karen and Beer, Craig
"High-Density Use of Septic Systems, Avon Lake, Iowa,"
Proceedings of the Iowa Academy of Science, 89(1), 1-6.
Available at: https://scholarworks.uni.edu/pias/vol89/iss1/3