The motivation behind preparing a watershed management plan for the LSR stems from known water quality problems within the Salamonie Reservoir. Sampling has shown particularly high levels of phosphorous, nitrogen, sulfates, total organic carbon, and total suspended solids. These elements increase the turbidity and fertility of the waters flowing into the Salamonie Reservoir, where blue-green algae blooms occur 2 to 3 times per year.
With most of the watershed contributing to the water quality problems in Salamonie Lake, Critical Areas were determined using both the windshield surveys and modeling of data to determine where best to begin implementing best management or conservation practices. Modeling of the watershed was completed using STEPL. STEPL stands for Spreadsheet Tool for Estimating Pollutant Loads, and was originally developed by the USEPA to assist State Non-Point Source Pollution project managers report load reductions to the USEPA. Purdue has developed a web-based version to make this program more available. The modeling considered several parameters including: soil types and properties, such as erodibility and hydric qualities; land use; septic system use; confined feeding operations, and other regional properties that can be applied to the entire watershed.
Windshield surveys were prioritized first in the development of the critical areas because they involve actual documentation of parameters that have been scientifically shown to cause water quality degradation. Water-quality modeling was prioritized second because, although it is an estimate, it looks at the entire sub-watershed area and can be used to make general comparisons between sub-watersheds.
Specific water quality data, both chemical and biological, were evaluated to determine if the data generally supported or didn’t support the critical area designations. Chemical water quality data, unless it exists in sufficient quantity for a proper evaluation, although valuable can be transient, and site specific. Therefor it was used only to add support to the critical area assignments. The biological data collected for the project was part of a volunteer effort using RiverWatch sampling and identification methods. This data was also used to help support the decision process for designating sub-watershed quality. The table below shows each sub-watershed, the tier designations for the windshield survey and three key parameters, and whether or not the chemical and biological data tended to support the tier designation, or there was some question. Where differences arise may indicate where further investigation needs to take place to determine if the data is indicative of a localized problem or indeed represents the overall quality of the sub-watershed. The designated critical areas are shown in the figure below.
Critical areas were evaluated and designated as either Tier 1, Tier 2, or Tier 3 watersheds depending on the severity of the problems. Tier 1 watersheds are believed to be the most degraded and are thus a high priority for implementation whereas Tier 3 watersheds are considered to be in the best condition, and are a lower priority. Tier 2 watersheds are intermediate. However, it should be understood that watersheds in all three tiers may benefit from best management practices to improve water quality and protect and enhance existing natural resources.