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Surface Water Quality Monitoring in the Geronimo and Alligator Creeks Watershed to Support the Implementation of the Geronimo and Alligator Creeks Watershed Protection Plan

Problem/Need Statement

In 2007, the TSSWCB Regional Watershed Coordination Steering Committee, using established criteria, ranked Geronimo Creek in the top 3 watersheds for selection of WPP development. The TSSWCB project 08-06 entitled, Development of a Watershed Protection Plan for Geronimo Creek, was begun in June 2008. The project included water quality monitoring, water quality modeling and WPP development. The development of the WPP for Geronimo and Alligator Creeks has been a stakeholder driven process lead by Extension with support from the GBRA. The Geronimo and Alligator Creeks Watershed Partnership (the Partnership) Steering Committee includes local officials, land and business owners and citizens and is supported by state and federal agency partners. With technical assistance from project staff, the Steering Committee has identified issues that are of particular importance to the surrounding communities, and has contributed information on land uses and activities that has been helpful in identifying the sources of nutrient and bacterial impairments, and in guiding the development of the WPP.

Historical data identified the impairment for bacteria and a concern for nutrients. The water quality monitoring program attempted to fill gaps in the historical data but was severely hampered by the drought of 2008-09. Data collection in the project further verified that periodic elevations of E. coli levels continue to exist. Routine ambient water quality data is collected at one site (12576) by GBRA through the Clean Rivers Program (CRP). Through projects 08-06, 11-06 and now 14-09, GBRA conducted water quality monitoring that included additional routine ambient and targeted stream sites on Geronimo and Alligator Creeks and three tributaries, and quarterly monitoring of springs, and wells.

The Geronimo Creek WPP has been completed and accepted by EPA. This monitoring project is warranted to provide critical water quality data that will be used to judge the effectiveness of WPP implementation efforts and serve as a tool to quantitatively measure water quality restoration. This effort will continue stakeholder engagement by maintaining the project website, participating in the watershed partnership meetings to provide technical assistance and to share water quality data, and to provide outreach and education to stakeholders including local schools, municipal officials, and the newly forming Guadalupe County Master Naturalists.

General Project Description

The sampling program will be continued in this project by retaining seven routine monthly sites and twelve targeted sites. The monitoring program will collect additional data, look for trends and fill data gaps identified in projects 08-06, 11-06 & 14-09. GBRA will continue to monitor the routine ambient monitoring location monthly under the CRP. One site will be located at Geronimo Creek at IH10 in order to collected routine and targeted monitoring downstream of the Oak Village North Subdivision. The City of Seguin has expanded its sanitary sewer service to the subdivision, taking the homes off of failing septic systems. The city is also completing an associated CWA Section 319 project that is funding the decommissioning of the septic systems, expediting the hook-up of individual homes onto the city’s collection system.

Project Workplan: 17-08

QAPP: 17-08

Final Report: 17-08

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