East Fork Above Lavon Site 3C Rehabilitation

East Fork Above Lavon Site 3C is located in McKinney, Texas. The site rehabilitation was completed in January 2003 at a nominal cost of $1,000,000. The rehabilitation of Site 3C was the first dam rehabilitation accomplished in Texas under amendments to the Watershed Protection and Flood Prevention Act (PL 83-566) which authorized NRCS to provide technical and financial assistance to watershed sponsors in rehabilitating their aging dams.

The spillway system was upgraded to allow the dam to safety perform and meet NRCS and State dam safety criteria. The existing principal spillway trash rack was replaced. An addition principal spillway was installed. A new impact basin was installed to accept water from both the existing and new principal spillway conduits.  A roller-compacted concrete (RCC) spillway was added to increase the flood handling capacity and reduce stress on the existing earthen auxiliary spillway.

M&E Consultants performed the rehabilitation planning and design, NRCS provided construction funding and construction oversight, and the local sponsors (City of McKinney) contracted for the rehabilitation construction.

M&E Consultants performed the following rehabilitation planning tasks:
• Preparation of POW per NRCS procedures *
• Preparation of final supplemental plan for NRCS procedures*
• Preparation of EA per NRCS procedures *
• Project management for planning dam rehabilitation *
• Alternative structural options
• Alternatives and structural options to minimize flooding impacts upstream and downstream
• Evaluation of alternatives and structural rehab options to reduce costs
• Address as many of the homeowners’ concerns as possible
• Supplemental Plan/EA was prepared in accordance with nine-step planning process, NWM       policy, P&G, NEPA, ESA, NHPA, and the state laws *
* Accomplished by a member of M&E while employed by NRCS.

M&E Consultants performed a turn-key dam rehabilitation design meeting NRCS criteria and involving the following tasks:
• Designed RCC structural spillway
• Provided principal spillway design options which were made a part of the construction                 contract in order to implement the most cost-effective option.
• Designed a special hooded inlet and trash rack.