CONSTRUCTION UPDATE Napa Plant Site Central Unit

Napa Plant Site – Central Unit Project Location

Major Design Elements

Construction Photos Channel Excavation

Construction Photos South Perimeter Levee Lowering

Public Access Features Construction Photos

Barge Channel Breach Construction Photos

MONITORING AND ADAPTIVE MANAGEMENT Napa Plant Site Central Unit

Water Quality Monitoring Water quality parameters: salinity, turbidity, temperature, pH, and dissolved oxygen (DO). Time: Data collected during an ebbing tide Frequency: –Within 3 days prior to breaching –Once during the first 24 hrs after breaching and again within 5 days after breaching –Weekly for the first month after breaching –Monthly until water quality objectives have been met for 3 consecutive months Per California Regional Water Quality Control Board

Sampling Locations 6 locations for Central Unit Breach. Shown on map as yellow dots NR-3 - Napa River, location 3 CUB-DS Central Unit Breach Downstream 150 ft CUB - Central Unit Breach CUB-US Central Unit Breach Upstream 150 ft NR-2 - Napa River, location 2 NR-1 - Napa River, location 1 Additionally sampled at the North Unit Breach (not included on following charts for clarity)

Salinity Performance Standard – Outflow from site will increase by no more than 5 ppt during any tide cycle. Results – Within performance standards BREACH 9/29/09

Turbidity Performance Standard – Outflow from site will not increase turbidity by more than 5 NTU during any tide cycle or by more than 10% if background is > 50 NTU. Results – Turbidity spikes in the first few days but returned to performance standards after 1 week. BREACH 9/29/09

Temperature Performance Standard – Outflow from site will not increase temperature by more than 2.8 o C in the wet season and 5.6 o C in the dry season during any tide cycle. Result – Within performance standards BREACH 9/29/09

pH Performance Standard – Outflow from site will not cause changes greater than 0.5 units of pH during any tide cycle. Results – Within performance standards BREACH 9/29/09

Dissolved Oxygen Performance Standard – Outflow from site will not decrease DO to a concentration lower than 5.0 mg/L during any tide cycle. Results – Within performance standards BREACH 9/29/09