BCRUA Deep Water Intake Alternative Site Study November 15, 2007

Project timeline Phase 1 – 30 mgd (summer 2010) – Floating intake – 78-inch raw water pipeline – Regional water treatment plant – Treated water pipelines to Leander, Cedar Park, Round Rock Phase 2 – 70 mgd (2016) – Deep water intake (may be accelerated depending on lake levels) – 84-inch raw water pipeline from intake to Phase 1 pipeline – Water treatment plant expansion

Phase 1 Intake Floating intake will utilize existing “Twin Creeks” barge Barge will be expanded with eight new pumps Expected to operate until deep water intake is constructed

Phase 1 Intake (cont’d) Twin Creeks Intake Cedar Park Intake View looking west from shoreline

Need for Deep Water Intake LCRA manages Lake Travis LCRA’s management plan predicts Travis may drop below elevation 576 in a severe drought An intake below 576 is required to ensure water is available in such a drought

Need for Deep Water Intake (cont’d) Deep water is only accessible near the original river channel The Volente area offers access to deep water and is in closest proximity to the BCRUA, Cedar Park, & Leander/LCRA plant site

Site Alternatives Study To determine which site is the most suitable for an intake structure Seven sites in the Volente area under study Four types of intakes under study

Site Alternatives Study (cont’d) Selection will be based on multiple criteria: – Minimizing cost – Compliance with regulatory requirements – Minimizing social impacts – Minimizing environmental impacts Elimination of all impacts is an unattainable goal

Site Alternatives Study (cont’d) Social impacts include: – Construction impacts (noise, dust, traffic disruption, etc.) – Aesthetics (visibility, architecture, lighting, noise, traffic, etc.) – Recreation impacts (restricted area, navigation hazards, etc.)

Site Alternatives Study (cont’d) Environmental impacts include: – Construction impacts (noise, dust, etc.) – Geologic impacts (groundwater, karst) – Habitat impacts (endangered species, particularly birds and karst invertebrates) – Water quality

Alternative Sites

Alternative Intakes Four types of intakes to be evaluated at each site: – Microtunnelled lake tap – Microtunnelled lake tap with remote pump station – Tower – Inclined pump

Microtunnelled Lake Tap

Microtunnelled Lake Tap (cont’d) Advantages: – No structure in lake – Maximum opportunity for aesthetic/architectural compatability with surroundings Disadvantages: – Second most expensive to construct – Cannot be located in flood plain – Must be within 1,200 feet of deep water

Microtunnelled Lake Tap with Remote Pump Station Similar to Microtunnelled Lake Tap, but a smaller gate shaft near the lake feeds water through a deep tunnel to a pump station further away from the lake A smaller building is located at the lake The larger pump station is located elsewhere

Microtunnelled Lake Tap with Remote Pump Station (cont’d) Advantages: – No structure in lake – Maximum opportunity for aesthetic/architectural compatability with surroundings – Gate shaft might be in flood plain with suitable design Disadvantages: – Most expensive to construct – Gate shaft must be within 1,200 feet of deep water

Tower Intake

Tower Intake (cont’d) Advantages: – Moderate construction cost – Can be constructed in flood plain Disadvantages: – Large structure in lake – Increased visibility

Inclined Pump Intake

Inclined Pump Intake (cont’d) Advantages: – Lowest construction cost – Pump station can be constructed in flood plain Disadvantages: – Inclined pumps have increased maintenance problems, and 2,000 HP installations are unproven – Pump barrels are exposed on lake shore

Site Selection Process Study Initiation – Public meeting to solicit comments and future participation Technical/Feasibility Review - Evaluate 28 alternatives for feasibility, cost, pipeline routing (approx 2 months) – Working meeting to discuss findings and review selection criteria and weighting factors Environmental/Social Impacts Review - Evaluate selection criteria (approx 2 months) – Working meeting to present preliminary selection and solicit input Finalize Selection - Evaluate comments and update selection matrix (approx 1 month) – Working meeting to present final selection

Questions & Comments  Please - Provide comments regarding: Selection criteria Alternative sites, any other potential sites within the study area Intake alternatives - Hold all questions relating to water rights, alternative sources, and participation in the City of Austin’s project