CFE agenda 110915 - Laserfiche WebLink

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1. Lake and Watershed Water Quality Monitoring CardnoEntrix, the consultant working for the UNRBA, completed the first 12 months of water quality sampling in July 2015. The Falls Lake Rules stipulate that in order for outside data to be evaluated during the re- examination of Stage II of the Falls Lake Rules, a minimum of three years of sampling data must be collected for the data to be considered by the Environmental Management Commission (EMC). The UNRBA's water quality sampling program is producing information for the following purposes: ♦ Determination of sources of nutrients in the watershed and the loading of nutrients from individual jurisdictions to Falls Lake; ♦ Falls Lake response modeling; ♦ Development of data for consideration of additional regulatory options; and ♦ Linkage of water quality conditions in Falls Lake to the designated uses of the Lake. Attachment 1 identifies the locations of surface water sampling stations for both the jurisdictional and lake tributary nutrient loading determination projects. All of the data collected is available for review at the web site set up for this purpose: http: / /unrba- wqp.cardno.com/ Attachment 3 is an example of the results obtained from water quality samples collected in five streams that feed into the northern end of Falls Lake. Fairly significant variations in these nutrient concentrations are seen among the five streams, as well as over the course of the time interval shown for two of the streams listed. Attachment 4 illustrates variations in the volume of stream flow in three streams in the upper portion of the Falls Lake watershed. The combination of nutrient concentration and rate of streamflow in each individual stream determines the amount (loading) of nutrients entering Falls Lake, so a stream that contains a low concentration of nutrients (such as Eno River) could actually contribute more nutrient loading if its' streamflow was significantly larger than a second stream with a higher concentration of nutrients (such as Ellerbe Creek). CardnoEntrix is also collecting data for the following Special Studies as part of the Falls Rules re- examination process: ♦ Falls Lake Constriction Point Monitoring ♦ High Flow Monitoring ♦ Storm Event Sampling ♦ Sediment Sample Analysis ♦ Light Penetration Analysis ♦ Volatile Suspended Sediment Determination ♦ Survey of Recreational Use of Falls Lake ♦ Model Performance Evaluation ♦ Evaluation of Regulatory Options to Falls Lake Rules