Authors: Ed Rhodes, Stephanie deVilleneuve, Allen Berthold and Dikshya Khanal

This document presents the strategy developed by the stakeholders of the Big Elm Creek watershed to restore and protect water quality in Big Elm Creek and the water bodies that flow into it. Stakeholders dedicated considerable time and effort in discussing the watershed, influences on water quality and potential methods to address water quality concerns, and selecting appropriate strategies to improve water quality. The ultimate success of the Big Elm Creek WPP achieving its goals depends heavily on the current and continued support from these individuals and agencies.

Authors: Emily Monroe, Lucas Gregory, Matthew McBroom, Carla Ethridge, Jeremiah Poling

The Attoyac Bayou Watershed Protection Plan (WPP) was developed by the Attoyac Bayou Watershed Partnership in 2009 to address the bacteria impairment in the watershed. This report covers the Attoyac Bayou Watershed Protection Plan Implementation Effectiveness Monitoring and Facilitation Continuation project (#19-53), implemented by TWRI, Angelina & Neches River Authority, and Stephen F. Austin State University from June 2019 through May 2021. It was funded by a State Nonpoint Source grant from the Texas State and Soil Water Conservation Board. The goals of this project were to facilitate and support effective implementation of the Attoyac Bayou WPP, to engage local stakeholders and seek input on future activities, to monitor water quality to illustrate implementation effectiveness, to encourage, track and assist with procuring financial assistance for adopting best management practices, and to coordinate and conduct relevant outreach and education activities in and around the watershed. 

Authors: Allen Berthold, Taylor Olsovsky

Segments of the Lavaca River have been identified as impaired due to excessive indicator bacteria. In response, a watershed protection plan was developed for the Lavaca River watershed to identify management measures that would reduce bacterial loads. One management measure identified in the watershed protection plan is the development of water quality management plans and conservation plans. The Texas State Soil and Water Conservation Board, local soil and water conservation districts, and the U.S. Department of Agriculture Natural Resources Conservation Service work with landowners to develop and implement such plans specific to each operation. These conservation plans include the implementation of best management practices, which may include financial and technical assistance as needed, that both improve operations and help reduce the amount of indicator bacteria that enters nearby waterbodies. However, raising awareness amongst landowners about available sources of technical and financial assistance can be a challenge. In-person programs are traditionally the primary method of education, but the impact can be limited when only a small number of people are able to attend.

Authors: Texas Water Resources Institute

Water quality monitoring indicates that sections of the Mission and Aransas rivers and Poesta Creek do not meet water quality standards for recreation because of elevated levels of Escherichia coli (E. coli) and Enterococci. The tidal segments of the Mission and Aransas rivers were first identified as impaired in the 2004 Texas Integrated Report and 303(d) List, while Aransas River Above Tidal and Poesta Creek segments were first identified as impaired in the 2014 Texas Integrated Report and 303(d) List. With the water quality impairments comes a need to plan and implement actions that restore water quality and ensure safe and healthy water for stakeholders. To meet this need, an assessment and planning project was undertaken to develop the Mission and Aransas Rivers Watershed Protection Plan.

Authors: Michael Schramm, Anna Gitter, Jackie Rambo, Stephanie DeVilleneuve, Ed Rhodes, Lucas Gregory

To facilitate development of a total maximum daily load in the Thompsons Creek watershed, we assessed methods for estimating mean daily streamflow in absence of a suitable long-term streamflow gage within the watershed. Continuous water levels were recorded at three sites in the watershed and combined with periodic 15-minute streamflow measurements to develop streamflow rating curves. The rating curves were used to calculate mean daily streamflow from measured depth data from May 2020 through March 2021. Three methods — drainage area ratio, linear regression, and generalized additive models — were used to estimate daily streamflows, and performance of each method was assessed against the rating curve calculated streamflows. Due to the lack of suitable streamflow gages, the drainage area ratio was determined to perform poorly in the Thompsons Creek watershed. Linear regression and generalized additive models provide acceptable performance for predicting daily streamflows and flow exceedance values. One station with a high proportion of no-flow days required the use of a two-step hurdle model that predicts the likelihood of flow and the volume of flow on a given day. Based on the results, ease of use, and model interpretability, we suggest using linear regression models at two sites and a generalized additive model at the third site to develop estimated daily streamflows for future total maximum daily loads.