Rio Grande - Manassa Conejos River & N Branch Stablization_Application

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Water Supply Reserve Account - Grant Application Form Fonn Revised May 2007 Relation of this project to the Rio Grande Compact - Surface water supply from the Conejos River and Rio Grande is subject to the Rio Grande Compact of 1938 between Colorado, New Mexico, and Texas to ensure that waters are equitably distributed between these entities. The Compact provides annual delivers- quotas for the Rio Grande and Conejos River to the Lobatos gauging station near the New Mexico state line in accordance with a separate deliver- schedule for each stream system. Anv failure to meet the Compact obligations could result in another lawsuit against Colorado by New Mexico and Texas, as occurred in 1966. With 42 years of uncontested Compact deliveries, Colorado has a stake in the success of this Project. Funding this project will enable the state to correct problems at a critical bifurcation on the Conejos, thereby preserving the Conejos River's ability to meet its obligations to the Rio Grande Compact. Need: The north bank of the Conejos River at the Project location has badly degraded over many years. During high flows, water cuts into the sand and clay bank. The potential for flooding the area north of the main stem is great. Land owners have repeatedly taken ineffectual steps to attempt to prevent firther erosion, but these efforts have not only failed to stabilize channel boundaries, they have often made the problem worse. This bifurcation point is undergoing accelerated bank erosion with increased bedload sedimentation and instability of the channel. Failed structures and human intervention in river bank changes throughout the years have exacerbated bedload deposition, contributing to firther deterioration of the Core and the Diversion Gates. This has led to a loss of channel capacity, generally degrading the stable dimension, pattern and profile of the river. MLI, its shareholders and all the beneficiaries of this system need surface rights to be delivered into the area. The state needs to get water into the forty two ditch systems in priority so that farmers can more efficiently irrigate in this agricultural region of Colorado. Colorado needs to fiend this Project and thus reduce or eliminate the very significant losses of Compact water which are occurring. Loss of the North Bank would severely jeopardize the Conejos River's ability to meet its portion of the Rio Grande Compact obligation. Problems/Opportunities: MLI has worked in this area of the river many times in attempts to correct years of stream bank erosion. Land owners and ditch companies have moved gravel, logs, and whole trees, and, with the help of Conejos County, have placed some rock in the streambanlc in attempts to prevent further damage. In retrospect, these efforts have been attempts to patch a symptom rather than to achieve a stable channel form. In recent tunes of severe drought. water was not being conserved. Increasingly unpredictable patterns of precipitation may cause heightened risk of flooding, such as occurred about a hundred years ago when the town of Manassa was two feet deep in water. In dry months it is difficult to deliver surface water rights into the area and to get water to the ditches in priority. The measures taken in the past have been crisis driven, limited bv_ lack of technical expertise and finds. MLI now has a great opportunity. in cooperation with NRCS, to install properly engineered river structures, J-hook rock formations which have been designed and have proven successful in numerous other river installations. NRCS has used this rock barb or J-hook design successfully in other places in the river, and it is now the preferred river stabilization technology used by the Conejos Water Consetvancv District. The opportunity exists now, through SB-179 funding, to address all of the above issues, installing a system which is based on a clear understanding of the river variables that encourage stability. Previous attempts have been incompatible with what D. L. Rosgen, professional hydrologist, calls the "rules of the river." Despite everyone's best intentions, local efforts were doomed to fail. With technical and funding assistance from NRCS, with the good counsel of the Rio Grande Basin Roundtable's Technical Assistance 19