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