Post on 15-Feb-2016
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USGS Groundwater Level Monitoring
William L. CunninghamActing Chief, USGS Office of Groundwater
Briefing to ACWI Workgroup
How to Sustain and Enhance High Quality Water Monitoring under Constrained Budgets
January 28, 2013
Monitoring Networks Outline• Background: Relevant GW Concepts• Existing Network• Proposed Network• Supporting Infrastructure
– DCPs and Telemetry
• Quality Assurance– Standards and Procedures
– Training
Why Measure Water Levels?Groundwater Provides
– About half of the Nation’s drinking water– About 40% of the Nation’s Public Supply– ~100% of “self supplied” water– 50 BGD for agriculture– Some to nearly all of streamflow
How Do We Make Water Level Measurements?
“Non-Standard” Measurements
http://www.youtube.com/watch?v=3IV1xVLIVM0
Microgravity
Sonic
Radar
Storage: SW vs GW
Surface Water Storage• Lake Mead: 9.3 trillion gallons
Groundwater Storage• Denver Basin Aquifer System
Paschke and others, 2011
Anderson and Woosley, 2005Bureau of Reclamation
Thinking in 3 Dimensions:NACP Aquifer System
• GW level monitoring must account for layered aquifers
• In many systems, water-level change within an aquifer also is important, and should be monitored.
North Atlantic Coastal Plain Aquifer SystemAreal Distribution of Wells
• Hypothetical example of 2-D coverage, Coastal Plain groundwater monitoring network
• Coastal Plain is blanketed with wells
• Example: Wells along section A-A’ providing good coverage for the State
North Atlantic Coastal Plain Aquifer SystemWell Distribution in Cross Section
• Wells provide good coverage of the Potomac aquifer– Surficial aqufier
unmonitored– Chesapeake aquifer
unmonitored– Castle Hayne-Aquia
aquifer unmonitored– Severn-Magothy aquifer
unmonitored
Existing Network
USGS Groundwater Level Expenditures2004-2006, 2012
Program FocusGWRP, CWP, and NSIP• Approximately $8M in “long
term” GW level data collection in FY12
• Much smaller than streamgaging expenditures: order of magnitude +
• Different focus of our respective Programs– Cooperator Choice– USGS Choice– Science
Annual Well CountWells with at least one measurement in NWIS
Wells with Discrete Measurements
• Decrease due to loss of state partners
• Increase due to increase in furnished record
• Fluctuations due to furnished record
Instrumented Wells Real Time and Non Real Time
• Most continuous wells are not furnished record
• Increased demand from cooperators in daily value/real time data
• Also reflects relative cost reduction of continuous record
Variable Frequency of Measurement
2013: Frequency of Measurement
• Furnished record often Annual or Biannual measurements
• >20K wells; about 7,500 quarterly or more frequently
State Examples—Frequency Distribution
Existing “Networks”: “Active” Wells
• Data must be in NWISWeb
• At least one measurement or site visit within last 13 months
• Any site, at any frequency
Existing Networks: Climate Response
• Open to a single, known hydrogeologic unit
• Known well construction • Located in unconfined
aquifers or near-surface confined aquifers that respond to climatic fluctuations
• Minimally affected by pumpage and likely to remain so
• Essentially unaffected by irrigation, canals, and other potential sources of artificial recharge
• Long-term accessibility • Well has never gone dry
(not susceptible to going dry)
Existing Networks: Springs• Spring reflects
concentrated discharge of groundwater at the land surface.
• Integrates hydrogeologic processes over large areas, and provides information about groundwater conditions as well as aquifer characteristics.
Proposed Network(s)
Climate Response Network
• ;
• At least one well within each of the 366 National Weather Service climate divisions
• Covers about 170 now• Network design includes
– real-time, continuous data collection to enable improved drought management;
– long-term records that provide a statisti cal framework for evaluating trends in our Nation’s ground-water resources;
– adequate areal coverage of our Nation’s principal aquifers and recharge areas to these aquifers.
(Cunningham and others, 2007)SECURE Act:....the Secretary shall....(B) by expanding the network of monitoring wells toreach each climate division, support the groundwater climate response network to improve the understanding of the effects of global climate change on groundwater recharge and availability
• Federal-State-Tribal collaboration USGS
• GW Levels and Quality
• Data available through common portal
• Data: guidance provided, but caveat emptor
A National GW Monitoring Network
Supporting InfrastructureDCP’s and Telemetry
• 10 years ago ~600• 13 years ago, ~300
Quality AssuranceStandards and Procedures
• Office of Groundwater Technical Memoranda
• Water Mission Area Policy Memos
• Survey Manual• TWRI’s and T&M’s• Annual Report Guide• NWIS Users Guides• Individual Office Policies• Office Quality Assurance
Plan
Quality Assurance• OGW policy requires tape calibration annually
Example: Tape Calibration
14 Tapes from 6 Vendors measured at manufacturer’s reference tension. Most tapes do not meet 0.01 ft accuracy at stated pull force.
• GW Field Techniques Class• GW Data Processing Class(es)• Annual Workshops
– Field methods, data processing, handheld data collection/entry……..
• Electronic Troubleshooting
Quality AssuranceWater Level Training
Discussion