This document summarizes options for accessing lake water supplies during drought conditions, including issues that may affect pumping from lakes, alternative strategies like temporary pumping and dredging, and associated permitting considerations. It provides an overview of 7 permitting options under the Clean Water Act and Rivers and Harbors Act that could authorize activities like sediment removal, including nationwide permits, regional general permits, and letter of permission procedures. Notification or application is required for some permits and multi-agency review may be involved, though exemptions and streamlined permits aim to facilitate drought response activities while protecting water resources.

1. Accessing Your Lake Water
Supply During Drought
Conditions
BRIAN COLTHARP & STEVE WATTERS
March 8, 2012
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2. How Bad is the Drought?
Mexico may export water
Fort Worth Star-Telegram
October 17, 2011
Drought brings toilet
to tap to fore
United Press International
August 23, 2011
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3. Overview
• Issues that May Affect Pumping from Lake
• Alternative Strategies
• Permitting Issues
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4. Issues That May Affect
Pumping from Lake
Physical Ability for Water to get to Pump Stations
Full
Drought
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5. Issues That May Affect
Pumping from Lake
Net Positive Suction Head (NPSH)
• Available (NPSHa)
• Required (NPSHr) set by pump manufacturer
• NPSHa = Patm + (Lake Elev. – Impeller Elev.) – Hsuct. – Vapor Press.
• Margin = NPSHa/NPSHr
= 1.3 or higher
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6. Issues That May Affect
Pumping from Lake
Minimum Submergence
• Distance from water surface to
suction bell
• Submergence Required (from pump mfr)
O 
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7. Issues That May Affect
Pumping from Lake
Pumping Capacity
Pump and System Curves
200
180
160
140
Pump AOR
120
Head (feet)
100
80
60
40
20
0
0 5000 10000 15000 20000 25000 30000 35000 40000 45000
Flow Rate (GPM)
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8. Alternative Strategies
Temporary Pumping
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9. Alternative Strategies
Temporary Pumping Considerations
1. How long will I have to do this?
2. Where do I need to pump to?
3. What type of pumps should I use?
4. How am I going to operate this facility?
5. How much will it cost?
6. How long will it take to implement?
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10. Alternative Strategies
Temporary Pumping Considerations
1. Time period to be in-service
– Own vs. lease
– Electric vs. generator
2. Pump to existing structure or all the way to destination
– Alleviate NPSH & submergence of existing pumps
– Flow & head considerations
3. Types of pumps
– Horizontal
– Vertical
– Submersible
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11. Alternative Strategies
Temporary Pumping Considerations
4. Ease of Operations
– Use of existing facilities
– User friendly
5. Costs
– Size & number of pumps
– Power requirements
– Length of piping
6. Schedule
– Availability of power & pumps
– Permitting
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12. Alternative Strategies
Dredging
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13. Alternative Strategies
Dredging Considerations
1. Undisturbed lake bottom vs. silt
– Availability of contractors
– Permitting
– Costs (recent bids $57/CY vs. $7/CY)
2. Equipment considerations
– 20’ to 30’ depth max for small dredge
– Accessibility
– Dredge power, electric vs. diesel
– Noise abatement needs
– Impacts on lake recreation and lake safety
– Increased TSS at treatment plants during dredging
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14. Alternative Strategies
Dredging Considerations
3. Cost considerations
– Mob/demob large percentage
– Economy of scale
– Impacts of rock, stumps and logs
– Distance to disposal site
– Availability of dredge contractors (this is a limited community of
contractors and availability can change quickly)
4. Dredge disposal
– Upland disposal lends to Nationwide Permit
– In-lake disposal requires at least LOP
– Large area, flat disposal site ideal
– Control of TSS from decant water
– Various disposal options – disposal pit, land application, rapid dewater
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15. Permitting for
Alternative Strategies
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16. Permitting Authority
• It’s my water, so why do I need a permit?
• Waters of the U.S. – governed by the U.S. Army Corps of
Engineers
– Section 10, Rivers and Harbors Act of 1899
• Navigation protection
– Section 404, Clean Water Act
• Water quality protection
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17. What’s Regulated
• The discharge of dredged material (33 CFR 323.2)
– Material excavated from waters of the United States
– Runoff or overflow from a contained land or water
disposal area
– The redeposit of dredged material other than
incidental fallback
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18. What’s NOT Regulated
• Discharges associated with onshore processing of
dredged material extracted for commercial use
• Activities involving only cutting or removing
vegetation so that root systems are not disturbed
• Incidental fallback of dredged
material
– the redeposit of small volumes of
dredged material incidental to
excavation activity…when such
material falls back to substantially the
same place as the initial removal
(33 CFR 323.2(d)(2)(ii))
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19. Permitting
• Good News…there are options:
– Some activities are exempt
– Sometimes Corps notification is NOT required
– General permits (Nationwide and Regional General Permits)
– Modified individual permits (Letter of Permission procedures)
– Standard individual permits
• Bad News
– Sometimes permits require Corps notification
– Sometimes multi-agency review is required
– Sometimes public notice is required
– It can take more time than you think
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20. Permitting Considerations
• Purpose and Need for dredging
• Area and volume of dredging
• Alternatives to avoid, minimize, and mitigate impacts
• Who owns/operates the lake?
• State-owned water body?
• Dredged material disposal site
• Handling of return flows
• Threatened and endangered species
• Historical and archeological
resources
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21. Corps Districts in Texas
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22. Permitting
• Issued in response to Texas drought
• Summarizes 7 existing permitting options
• Intent – to streamline authorization by informing
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23. Public Notice Overview
• “Drought conditions do not diminish federal jurisdiction”
• Some permits require application or PCN
• Compensatory mitigation may be required
• Regional and General Permit Conditions always apply
• Section 401 Water Quality Certification Conditions always apply
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24. Permits
• NWP 3(b) – Maintenance
– Preconstruction notification (PCN) required for sediment removal
– No volume or area limits (according to Public Notice)
– Sections 10 and 404
• NWP 12 – Utility Line Activities
– Applicable for temporary pumping facilities
– PCN required sometimes
– 1/2 acre impact limit
– Sections 10 and 404
• NWP 16 – Return Water from Upland
Contained Disposal Areas
– PCN and individual 401 certification required
– 300 mg/L TSS limit
– Section 404
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25. Permits
• NWP 19 – Minor Dredging
– No PCN
– Maximum volume = 25 cy
– Sections 10 and 404
• NWP 35 – Maintenance Dredging of Existing Basins
– Sediment removal around existing marinas, boat docks, etc.
– No PCN
– Dredging limited to previously authorized depth of basin
– Section 10
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26. Permits
• Regional General Permit (RGP) 2 – Utility Lines and Intake and
Outfall Structures
– Allows for temporary structures to operate existing intake facilities
– PCN required
– 1/4-inch mesh intake screen, 1/2 ft/second max intake velocity
– Sections 10 and 404
• RGP 8 – Boat Ramps and Minor Facilities
– 200-ft dredging limit
– PCN triggers:
• 1/10-acre PCN limit
• Impacts to forested wetlands
• Sediment return flows to waters of U.S.
– Sections 10 and 404
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27. Permits
• LOP 1 - Letter of Permission Procedure for Activities at Certain
Reservoirs and Federal and State Sponsored Projects
– Allows sediment removal and other activities
– Application letter required
– Agency consultation typical
– Sections 10/404
• LOP 2 - Letter of Permission Procedure for Excavation Activities
– Allows sediment removal, primarily
– Application letter required
– Agency consultation typical
– Sections 10/404
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28. Permits
• Programmatic General Permit-2 (PGP-2) - Activities Authorized by
Lower Colorado River Authority Lakewide Permits
– Allows dredging
during lakewide
drawdowns.
– Apply to LCRA
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29. Permit Timing
• After PCN/application filing:
– NWPs w/o PCN – good to go immediately
– NWPs with PCN – allow at least six weeks
– RGPs – allow at least six weeks
– LOPs – allow at least eight weeks, often more
– Standard IP – allow at least six months
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30. Accessing Your Lake Water
Supply During Drought
Conditions
BRIAN COLTHARP & STEVE WATTERS
March 8, 2012
30