Matagorda Bay and Nearby Coastal Waters Dissolved Oxygen and pH TMDL Assessment Report

Abstract

This project provides technical support to the Texas Commission on Environmental Quality (TCEQ) for the development of a Total Maximum Daily Load (TMDL). The TCEQ will lead an effort to assess the causes and sources of the following water quality problems identified in the 2002 Texas Water Quality Inventory and 303(d) List for Matagorda Bay/Powderhorn Lake (Segment 2451), which only partially supports the aquatic life use due to exceedence of the dissolved oxygen (DO) standard on the east half of the main bay; Tres Palacios/Turtle Bay (Segment 2452),which only partially supports the aquatic life use due to exceedance of the dissolved oxygen standard in the Palacios area assessment unit and Carancahua Bay (Segment 2456); which only partially supports the general use due to high pH in 9.2 square miles at the north end of the bay; and Carancahua Creek and Conn Brown Harbor (Segment 2483A), which does not support the aquatic life use in the entire harbor due to depressed dissolved oxygen. The goals of the current project were to develop a Quality Assurance Project Plan, to develop and implement a monitoring program to assess the DO conditions in Matagorda Bay, Tres Palacios Bay, and Conn Brown Harbor and the pH conditions in Carancahua Bay, and to assess the data collected from the monitoring plan and determine the cause of impairments that result in exceedence of the water quality criteria.