BCRUA Deep Water Intake Alternative Site Study

1. BCRUA Deep Water Intake Alternative Site Study November 15, 2007

2. 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

4. 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

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

6. 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

7. 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

8. 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

9. 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

10. 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.)

11. 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

12. Alternative Sites

13. 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

14. Microtunnelled Lake Tap

15. 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

16. Microtunnelled Lake Tap withRemote 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

17. Microtunnelled Lake Tap withRemote 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

18. Tower Intake

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

20. Inclined Pump Intake

21. 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

22. 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

23. 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