Rehabilitation and reconstruction of Tisdale Weir will address the weir’s documented structural deficiencies. Some components will be rehabilitated by completing minor modifications to the existing structure, and others will require demolition and full reconstruction. The weir crest will be repaired, and the two abutments (south and north) and the energy dissipation basin will be demolished and reconstructed. The proposed reconstruction of the energy dissipation basin will be directly coupled with construction of the proposed fish passage facilities. The fish passage facilities constructed for the Project will include reconstruction of an integrated energy dissipation to include a fish collection basin on the downstream side of the weir; installation of a notch, an operable gate (for flow regulation), and attendant facilities at the north end of the weir; construction of a channel connecting the notch in the weir to the Sacramento River; and installation of baffle fishway elements inside the connecting channel. A multi-purpose concrete or roller-compacted concrete energy dissipation and fish collection basin (basin) will be constructed on the downstream side of Tisdale Weir, occupying approximately 2 acres from the weir downstream. The existing energy dissipation basin on the downstream side of the weir will be removed and replaced to provide necessary energy dissipation, reduce fish stranding, support fish passage to the notch, and improve operational flexibility for maintenance and, if necessary, any fish rescues.