Reports

The ultimate goal of the Silver Lake Association (SLA) is to restore the lake so it’s safe to swim, kayak, and fish. South Dakota’s Department of Agriculture and Natural Resources (DANR) has clearly outlined criteria in order for a lake to be assigned the use of immersion recreation (swimming) and fish, wildlife, propagation, recreation and stock watering. Below we have outlined the criteria (Source: The 2024 South Dakota Integrated Report for Surface Water Quality Assessment):

  • Immersion Recreation

    • E. Coli (per 100ml) - <126

    • Microcystin (mg/L) - <8

    • Cylindro-spermopsin (mg/L) - <15

    • Oxygen (mg/L) - >5

  • Fish, wildlife, propagation, recreation and stock watering

    • Conductivity (mg/L) - <4,000

    • Nitrates (mg/L) - <50

    • pH (standard units) - >6 - <9

    • Solids, total dissolved (mg/L) - <2,500

    • Total Petroleum Hydrocarbons (mg/L) - <10

    • Oil and Grease (mg/L) - <10

SLA will set its water quality goals with the criteria listed above.

In order to get a better understanding as to where the lake has the most room for improvement, SLA first reviewed the data available via the DANR Water Quality Monitoring Access Portal. While this gave a us a good benchmark for dissolved oxygen, pH, and other criteria, it did not include other important tests such as ammonia, nitrates, and E. coli. As a result, SLA decided to conduct multiple rounds of water tests in the spring of 2024. See results below.

The test results reviewed that E Coli levels were extremely high in and around the lake. For example, one test result from the “HWY 81 Culvert” showed an E. coli result of 17,230 mpn/100ml, well over the DANR limit of 126 for immersion recreation.

The E. Coli test result from “West Side Silver Lake” was 1,203 mpn/100ml, which was 855% over the immersion recreation limit of 126. See below how that compares to the weighed average of all easter lakes in South Dakota, according to DANR.