LCRA Lane City Reservoir Project, Karen Bondy
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LCRA Lane City Reservoir Project, Karen Bondy
- 1. Karen Bondy, P.E. LCRA Senior Vice President of Water Resources March 2, 2017
- 4. Region K Water Planning • 2020-2070: Water demands increase 24 percent – From 1.2 million to 1.5 million acre-feet per year • In 2070: Potential water shortfall of 512,000 acre-feet
- 5. LCRA’S WORK TO EXPAND THE WATER SUPPLY
- 6. Expanding Water Supplies • Using groundwater in Bastrop County – Drilled wells at Lost Pines Power Park – Purchased groundwater rights at Boy Scout ranch • Completing design, permitting and land acquisition for additional water projects • Building a new downstream reservoir – Lane City Reservoir
- 7. Lane City Reservoir • Located in Gulf Coast Irrigation Division • Off-channel reservoir/ring dike • Existing river pump station and canals • Storage volume about 40,000 a-f • Annual firm yield acre-feet/yr 90,000 • Cost is $250 million 7
- 8. Why Build the Lane City Reservoir Downstream? • Take advantage of a wetter climate in lower basin • Capture and store runoff from rain falling downstream of Lake Travis • Increase system efficiency • Water demand
- 9. Major Permitting Efforts • Water right amendment • USACE Sections 404/10 permitting • Engineering design permits Floodplain permitting Dam safety permitting • TPWD sand, gravel and marl permitting • TPDES construction storm water discharge permit 9
- 10. Lane City Reservoir Project Components
- 11. Lane City Reservoir Lane City Reservoir Overlaid on Austin Map 0 0.5 mile
- 12. 12 Reservoir Drains and Cut-off Wall
- 13. Technical Review Board • Includes leading engineering experts – Dr. Michael Duncan and Dr. Stephen Wright – Highly respected by TCEQ 13 Engineering textbook
- 15. Embankment and Lime Stabilized Fill CONFIDENTIAL - REFLECTS INTERNAL POLICY DEVELOPMENT AND/OR LEGAL ADVICE 15 11/29/2016
- 16. Relift Pump Station Components 16 Reservoir Relift Pumps Stand-Pipe & Control Room
- 18. Inlet to Relift Pump Station 18
- 19. River Pumps, Return and Canal Horizontal Pumps Vertical Pumps Main Canal River Return
- 21. Fish and Mussel Relocation 21
- 22. EFFORTS TO IMPROVE WATER MANAGEMENT
- 24. Prairie Conservation Reservoir • $8 million grant from NRCS – for 2,000 acre-foot reservoir • Will provide water for use in the Lakeside Irrigation Division • Will enhance operational efficiencies – Potential to save up to 20,000 acre-feet of irrigation water ordered from the Highland Lakes in a typical year 24
- 25. Questions?
Notes de l'éditeur
- Welcome. I’m excited to be here today to discuss an exciting new water supply project LCRA is working on. The Lane City Reservoir is the first significant new water supply in the basin in decades. But before I talk about the reservoir, I’d like to give you a snapshot of our basin.
- We are the Lower Colorado River Authority, and this is the Colorado River in our name. First, this is not the Colorado River that flows through the Grand Canyon. This Colorado starts in West Texas and flows to Matagorda Bay on the Gulf of Mexico, It begins and ends in Texas. It’s the longest river in Texas – 862 miles long. LCRA manages the lower two-thirds – the lower part of the river, About 600 miles between San Saba and Matagorda Bay. (Click to make map of Texas smaller and reveal a map of the Highland Lakes) Inside the red box on the map are the six Highland Lakes and dams on the river – The lakes are northwest of Austin in the Texas Hill Country. LCRA built six dams on the lakes from the 1930s and early 1950s. Two of those lakes – Buchanan and Travis – are LCRA’s water supply reservoirs for the region.
- A reliable supply of water is critical to a growing region like ours, and it takes a lot of planning to ensure supplies can meet demands.
- The latest state water plan is the 2017 Water Plan, and in it, Region K water demands are projected to increase by about 24 percent between 2020 and 2070 – from 1.2 million to 1.5 million a-f per year. Region K’s existing water supplies are expected to decline by less than 1 percent between 2020 and 2070 – from 999,000 to 992,000 a-f per year. Water user groups face a potential water shortage of 512,000 a-f per year in 2070 in drought of record conditions. The water management strategies recommended in the TWDB State Water Plan would provide 745,000 a-f per year in additional water supplies to water user groups 2070. The Lane City Reservoir we’re about to discuss is one of those strategies. A new hydrologic critical period has reduced the lower Colorado River system’s firm yield Based on 1947-57 drought, firm yield was 600,000 acre-feet per year Based on new critical period, firm yield is about 500,000 acre-feet per year Because of the record low inflows during the recent drought, we experienced a new hydrologic “critical period.” A critical period is the time period in which the driest conditions occurred from a water supply perspective. The inflows during that period define the hydrology LCRA uses to calculate how much water the lower Colorado River system can supply. Our “critical period” was the drought of the 1950s. Now we believe it’s the most recent drought and – as such – the firm yield is less. Firm yield is the amount of water the lower Colorado River system can supply every year in a repeat of the driest conditions on record. Based on the drought from 1947-1957, the system firm yield (total water supply) was 600,000 acre-feet per year. With the most recent drought as the new critical period, the firm yield of the system is reduced. We estimate that the reduction is about 100,000 acre-feet per year. This would leave the firm yield at 500,000 acre-feet per year. Again, this is an impact to the overall system. Water rights that have storage associated with them are less affected than those that don’t.
- LCRA is aware of the need for more water supplies to meet growing demands, and we’re working aggressively to expand the supplies.
- Here is some of what we’ve done and projects we are working on: LCRA has drilled 4 GW wells on LCRA property in Bastrop County. Can produce up to 10,000 AFY. Serving the Lost Pines Power Park in Bastrop County; reduced need for SW. Purchased the groundwater rights at the Boy Scout ranch near LPPP. More projects in the pipeline for Central Texas: Conjunctive use of SW, GW, and treated effluent. Brackish groundwater. We plan to invest more than $43 million over the next five years to complete as much of the design, permitting and land acquisition as possible for additional water projects, so we’ll be ready to proceed when a customer approaches us with a need for those new supplies. Looking for smart options that provide opportunities for multiple “plays.” LCRA is working on a new downstream, off-channel reservoir. The largest project is the Lane City Reservoir in Wharton County – first new reservoir in Colorado River basin in decades. It will add up to 90,000 acre-feet to the region’s water supply. Will make up for a change in the firm yield. The most recent drought surpassed the drought from 1947-57 as our critical period, so the firm yield of the lower Colorado River system was reduced by about 100,000 acre-feet per year. Firm yield now is about 500,000 acre-feet per year.
- Let’s talk more about the Lane City Reservoir, which will be constructed off the main channel of the Colorado River near Lane City in Wharton County. Why build the new reservoir so far downstream when the bulk of demand is up in Central Texas, where the population is greater? The answer lies in the location of the Highland Lakes we just discussed. Here is Lake Travis, and we currently have no ability to capture rain that falls below Lake Travis. But look at how much more it rains closer to the coast – the lakes’ watershed gets 25-30 inches of rain a year – but down by the reservoir site they get almost 50 inches of rain a year. We have no way to capture any of that and hold it for beneficial use right now. But by building the reservoir in Lane City, we can store some of that water and hold it until it’s needed by customers in the area. We will pump water out of the river and store it in the reservoir, then pump it back into the river when customers need it. Right now, when customers in the downstream area need water and flow in the river is not high, we send water downstream to them from the Highland Lakes. It can take as long as a week for the water to get there, and in that time it may have rained and the water is no longer needed. In addition, you have evaporation and seepage – so the amount of water that arrives is less than the amount of water that sent. With the new reservoir, we can store water closer to where it’s needed, making the entire system more efficient and better serving customers in the area. Direct customers could include industry, agriculture or any customers in that immediate area, but the reservoir benefits the entire basin, not just customers in the area. Storing water downstream, closer to where it’s needed, reduces demands on the Highland Lakes.
- The reservoir is a complex project made up of a 40,000 acre-foot off-channel reservoir, canal improvements and pumping stations to move water – which all must be able to withstand hurricane-force winds on the Texas Gulf Coast. The area of the reservoir is 1100 acres. Here are the key project components: ((SPEND SOME TIME ON THIS)) Reservoir. Relift pump station and outlet. Expanded canal. – ((EXPLAIN IRRIGATION DIVISION)) River intake pumps (rehabbed). ((EXPLAIN EXISTING PUMP STATION)) New outfall station. – water needs to be returned to the river to serve downstream customers
- Just how big is this reservoir? Here it is outline over downtown Austin. It would stretch from Mopac to I-35, from Cesar Chavez to MLK Blvd.
- The Lane City Reservoir is not just a lake. This reservoir is essentially a 5-mile circular berm. Let's examine this berm in more detail. With an average depth of water of 40 feet, plus 5 feet of freeboard, from toe to toe, the berm cross-section width is about the length of a football field (375 feet wide). And because of the high variability of the soil on site, we need drains and cut-off walls. In this graphic, the left side is the inside of the reservoir and the right side is outside. The left side is wet and the right side is dry. You can see from this schematic that we’ve determined that there are pockets of sand intermingled in the clay below the reservoir. Even though we have a clay liner, the soil beneath the reservoir will tend to be saturated, which is expected. However, we don’t want water migrating (moving) UNDER the berm, through the sand pockets. That could undermine the berm. We had to create the cut-off wall, the black line, which is up to 80 feet deep. It’s filled with bentonite clay – essentially impermeable. Also, controlling seepage THROUGH the berm is critical. A sand filled drain (called a “chimney” drain) inside the embankment collects seepage and transports it outside the berm. All reservoirs seep water, but seepage can erode and weaken the embankment. Could lead to failure without the cut-off wall and drains. SHORTER VERSION: The Lane City Reservoir is not just a lake. In addition to the dam, the reservoir requires drains and cut-off walls because: High variability of the soil on site. Controlling seepage is critical. All reservoirs seep water, but seepage can erode and weaken the embankment, and lead to failure if the cut-off wall and drains aren’t engineered correctly. The highest risk for failure is when filling the reservoir. The Lane City Reservoir will be filled and refilled multiple times a year.
- A reservoir like this has not been built in Texas since STP was constructed in 1975. There are very few reservoirs in the country subject to hurricane force winds. So there’s not a lot of engineers or contractors with this type of experience. To ensure safety at high hazard dams such as the Lane City Reservoir, TCEQ guidelines advise setting up an independent technical review board which we have done. The board reviews the reservoir design and assesses the risks. LCRA’s independent technical review board includes Dr. Michael Duncan and Dr. Stephen Wright, the people who literally “wrote the book” on reservoirs like the Lane City Reservoir. TCEQ highly respects them, as do we. They work for us as a 2nd set of eyes. So you can see the new reservoir is actually a highly complex system of over 7 million CY of select materials built to withstand extreme conditions It has been designed properly to be save and reliable and meet TCEQ dam safety code. I’ll next review the project status. Please turn to page 9.
- Aerial Looking S.W. Note: (Click to reveal red circle) Corner - completed embankment (Click to reveal red circle) Soil cement plant in center (Click to reveal red circle) Inlet/outlet pipe 120” Wet Photo date: 1/27/2017
- Photo taken: 2/13/2017
- Here’s a plan view of the river pump station site, which is made up two separate existing pump stations, and a new outfall station Rehabilitated horizontal pumps (original construction 1948). Rehabilitated vertical pumps (original construction 1967). Both of these pump stations have intakes located on the river, and they discharge into the main canal. Rehabilitated main canal (original construction 1930). New river outfall construction (2017).
- Photo taken: 2/12/2017 Aquatics – Dec.16th, AEP now out of river area To be totally out – end of January.
- We also will be building a much smaller reservoir – the Prairie Conservation Reservoir – in Colorado County. It will help LCRA supply water more efficiently.
- U.S. Department of Agriculture Natural Resources Conservation Service announced its intent to award LCRA and its partners in December $8 million for the Prairie Conservation Reservoir, which is a very different type of project than the Lane City Reservoir. Located off the main channel of the Colorado River near Eagle Lake in Colorado County. Located in LCRA’s Lakeside Irrigation Division, which has traditionally served about 28,000 acres of irrigated farmland (mainly rice). Site is close to canals and an existing LCRA irrigation water re-lift pumping plant. LCRA already owns the land. The LCRA Board of Directors approved purchasing the land in 2014.
- Prairie Conservation Reservoir: Much smaller than the Lane City Reservoir – just 2,000 acre-feet. Will work as a balancing reservoir within the Lakeside Irrigation Division. Will be filled from river flows during the off-irrigation season to provide initial water to Lakeside canals at the start of each season and during the irrigation season, will serve Lakeside water customers. Primary purpose is to enhance operational efficiencies within the Lakeside Irrigation Division. Does not increase firm supply. Could reduce reliance of these customers on stored water from the Highland Lakes. Potential to save up to 20,000 acre-feet of irrigation water ordered from the Highland Lakes in a typical year.
- LCRA is very excited about our water projects, especially the Lane City Reservoir (shown here in a rendering), and how they will allow us to continue providing Texans with a vital service. The total diversion for the past 12 months could have been enough to fill the reservoir more than 6 ½ times We know how important water is to the success of this booming region and are dedicated to expanding supplies.