Caddo Lake Institute

Environmental Flows Project
Caddo Lake and its Tributaries

Progress / Meetings and Workshops / Supporting Documents


The Cypress Basin Flows Project was initiated in 2004 by the Caddo Lake Institute and the Nature Conservancy (TNC) in partnership with U.S. Army Corps of Engineers and others.   

This project was started after the State made the decision that no new water rights would be granted for protection of flows in rivers, lakes and bays.  Instead, the state proposed, and has now enacted, a law (Senate Bill 3) to provide a process for setting aside water for instream flows in Texas.

Goal and Objectives

The project seeks to assure adequate instream flows to sustain the ecological, recreational and economic values of Caddo Lake, its watershed, and the Cypress Basin.

To reach its goal, the Project has these objectives:

1. An Environmental Flow Reservation or Set Aside: i.e., The Project is developing a basis to seek a state approved reservation of water for environmental flows in the Caddo Lake watershed, reflecting the flow regimes needed to restore and maintain the ecology and water quality of the system and to enhance economic development in the region.

2. A New Release Rule for Lake O' the Pines:  i.e., The Project is also providing a technical basis for a change in the operations of the dam by the North East Texas Municipal Water District and the Corps of Engineers for a more natural pattern of releases needed downstream in Big Cypress Creek and Caddo Lake, while assuring flood control, water supply and the other purposes of the reservoir.

3.  Adaptive management for the long term:  The Project will continue to obtain new information and refine environmental flow regimes based on experimentation, research and further analysis.


Based on a series of meetings with natural resource experts from Texas and elsewhere and with the stakeholders in the watershed, the Project resulted in "Building Blocks" or "environmental flow regimes" to provide for variations in annual and seasonal flows that will best protect fish and wildlife that are dependent upon a healthy ecosystem. Those building blocks then became the scientific basis for the project's recommendations for environmental flows standards and strategies. An adaptive management approach will continue to be used, where Building Blocks, standards, and strategies are developed, tested in the field, and adjusted as a better understanding of the flows and their roles is developed.

The Project is relying upon 1) the experience of the TNC-Corps of Engineers Sustainable Rivers Program in other parts of the country; 2) recommendations of the methodology developed by the National Academy of Sciences for the State of Texas on protection of environmental flows; and 3) several recent Texas laws on environmental flows.  Much of the scientific work needed to reach the objectives has been completed as part of this project.

Meetings, Workshops and Fieldwork

2014 Cypress Basin Bioblitz

October 15, 2012 Science Meeting

December 12-14, 2011 Workshop

April 6, 2011 Science Meeting

November 16, 2010 Stakeholders Meeting

December 2008 Workshop

July 2008 Aquatic Biology Meeting

Spring 2007 Planning Meetings

October 2006 Workshop

Spring 2006 Planning Meetings

May 2005 Workshop

December 2004 Orientation Meeting


Supporting Documents

SRP Floodplain Inundation Analysis Report (May 2012)

2010 Environmental Flow Regime and Analysis Recommendation Report

Environmental Flows Press and Outreach

U.S. Army Corps of Engineers New Modeling for the Cypress Basin

Background Documents


Additional information on Caddo Lake and its watershed can be found on CLI's data website -


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