Connecting the Dots...Groundwater, Surface Water, and Climate Connections in the Northwest: Alphabetical Content Listing

Climate Change Adaptation

Climate Change Impacts on Groundwater: More Than Just Drought

Bruce K. Daniels, Ph.D.
We all know that a lack of precipitation (AKA drought) impacts groundwater recharge. But few know the proportionality between changes of precipitation and recharge. For example, does 10% less precipitation cause 10% less recharge? To illustrate this distinction, precipitation examples are shown which produce the same amount of annual precipitation, but when applied to hydrology models they yield quite different reductions of recharge.

Statistically significant trends in precipitation timing patterns have been calculated from the decades of daily climate observations from many weather stations. Applying these timing trends to local basin hydrology models without any change in total precipitation, produces substantial changes in recharge.

Change of temperature alone might cause impacts on groundwater recharge. The ET fraction of total precipitation can be quite high at 50%–70%. Therefore even a moderate increase in such ET could represent a considerable water loss. This is demonstrated by applying the predicted 7°F temperature increase to basins and showing the impacts on groundwater recharge.

Predictions of West Coast sea level rise are as much as 4½ feet. Coastal basins can only be protected from the additional seawater intrusion induced by this sea level rise through a corresponding rise of inland water levels. It is shown how such a protective action can be translated into a virtual loss of recharge. In other words, some recharge has no value for gaining supplemental supply, but instead just worthwhile for offsetting sea level rise impacts.

Note that I did present a similar talk at the NGWA conference last month in New Mexico. Dr. John Hawley, another presenter, said I need to be a keynote speaker in as many water meetings as possible. With such encouragement I am trying to see if you have an interest in this talk too.

Future of Groundwater

Maria Gibson
More than 1.5 billion people rely on groundwater resources worldwide. Water scarcity and difficulty in management is a reality many will face as global population is expected to increase and climate-driven changes intensify demand. As climate is expected to impact groundwater resources, scientific research and advances in technology may provide practical mitigation strategies to offset predictive changes. The goal of this presentation is to provide a glimpse into innovative groundwater developments and its function in a water resource management environment. Cutting-edge research, including the next generation of GRACE: Grace Follow-On Mission, advances in 3-D printing of porous media, Unmanned Aircraft Systems in groundwater quantification, and upcoming trends in model integration will also be presented.

Groundwater in California Cascade Aquifers: First-Magnitude Springs and Regional-Scale Storage and Flow

Lee Davisson
Northeastern California Cascade region contains 22,000 km2 of hard volcanic rock aquifer consisting mostly of surficial Neogene and Quaternary age basalts. Based on stable isotope evidence, volcanic centers of Mt. Shasta, Medicine Lake Volcano, and Lassen Peak are focal points of high elevation groundwater recharge that flows 20-50 km in these aquifers before emerging as first-magnitude spring flows. In total, these spring discharges are estimate at ~85 m3/s, forming the upper Sacramento River which supplies an annual critical base flow to the 5.7 million m3 Shasta Reservoir storage, provides a source of the >2000 gigawatt-hours of hydroelectric power, and supports unique spawning habitat for thermal- and nutrient- dependent native and endangered aquatic life. This volcanic aquifer area has never been comprehensively investigated and is currently under-recognized in California State water management. Recent baseline monitoring of discharge in the western portion of the Fall River Springs (34 m3/s) shows strong correlated response to regional precipitation recorded 50 km up-gradient in the recharge area, suggesting preferential fracture-driven flow paths traversing many kilometers. Distinct flow paths are further indicated in measured temperatures of individual discharge points <1 km apart distinguished by 9.0°C versus 12.5°C and electrical conductivities 105 mS versus 145 mS that remain constant throughout the year. The δD and δ18O further shows either a consistent, distinct recharge source mixture or an evaporation influenced snow-melt process driving differences in isotopic compositions between different discharge points. Higher temperature and electrical conductivity also is associated with magmatic helium, although corrected 3H-3He ages suggest groundwater storage times of <30 years. Accordingly, changes in aerial groundwater storage is captured by inter-annual differences in late summer base flow discharge in downstream rivers and records intra- and inter-decadal climate cycling. Furthermore, this spring-fed base flow during extended droughts showed 20-50% decrease in volumetric discharge.

Regional Transport of Heat by Groundwater: Implications of Climate Change

Erick Burns
Changes in groundwater temperature resulting from climate-driven boundary conditions can be evaluated using new analytic solutions of the groundwater heat transport equation. These steady-state solutions account for land-surface boundary conditions, hydrology, and geothermal heating, and can be used to identify the key physical processes that control thermal responses of groundwater-fed ecosystems to climate change; in particular: (1) groundwater recharge rate and recharge temperature and (2) vadose heat conduction controlled by land surface temperature and vadose zone properties. In addition to the steady-state solutions, transient solutions of thermal response are used to estimate how long it takes for new thermal signals to arrive at groundwater-dependent ecosystems. The Medicine Lake Highlands, California, USA, and associated springs complexes are used to demonstrate the methods, providing quantitative estimates of the magnitude and timing of spring temperature changes as a function of position within the hydrologic system.

Drought Resilience/Water Availability/Scarcity

William Alley, Ph.D.

An Approach to Understand Water Quality Trends in Groundwater in the Columbia Plateau, Washington, Oregon and Idahi

Terrence Conlon
Groundwater of the Columbia Plateau basaltic aquifer in Washington, Oregon, and Idaho was sampled as part of an assessment of water-quality in principal aquifers of the United States conducted the U.S. Geological Survey National Water-Quality Assessment Project. The Columbia Plateau principal aquifer consists of the basaltic rocks of the Columbia River Basalt Group. Water from approximately 60 wells in Oregon, Washington, and Idaho was collected and analyzed using nationally consistent protocols for a suite of constituents including major ion chemistry, nutrients, radiochemistry, volatile organic compounds, pesticides, pharmaceuticals, trace elements, stable isotopes of water, and age-tracers. The groundwater quality information will be used to understand water quality for comparison with past and future conditions, evaluate horizontal and vertical variation in water quality, and assess the source, age, and sustainability of groundwater supplies.

City of White Salmon Aquifer Storage and Recovery — Completing the Water Supply Puzzle

Tim Flynn, LHG, CGWP
Municipal water systems face continual challenges providing safe, reliable water supplies for their communities. These challenges can include physical constraints, such as declining aquifer yield, and compliance with regulatory requirements, such as water right permitting and water treatment standards. This talk discusses the City of White Salmon’s (City) aquifer storage and recovery (ASR) project and its ability to deliver both physical and regulatory water system solutions.

The City was historically served by a high quality surface water source from Buck Creek, a tributary of the White Salmon River. When compliance with increased surface treatment standards proved costly, the City, in partnership with the City of Bingen and Port of Klickitat, developed a new groundwater well field to replace surface supplies. The well field was initially highly productive, but has shown significant decrease in yield over time. Additionally, the City faced shortages in the annual water supply authorized under their water rights, forcing a moratorium on new connections.

In response to these shortages in both source yield and regulatory authority, the City seeks to improve supply reliability by pursuing an ASR project to take seasonally available winter flows from the new treatment plant, inject treated water into a City production well, and recover water during peak summer demands. The ASR project just finished the pilot testing stage, which showed the City can expect to inject, store, and recover about 100 acre-feet per year, and thus provide approximately 25% of peak (summer) demand.

Effects of Beaver Dams on Groundwater Elevation and Temperature in an Incised, Semiarid Stream

Carol Volk, PhD
In hot summer months the base flow of small, semi-arid streams is typically low and instream habitat available to biota is limited.  This can limit water exchange between floodplains and channels, impairing instream habitat important for maintaining communities of stream and riparian biota. The presence of beaver dams or man-made beaver dam analogs (BDAs) can cause sediment deposition and overbank inundation can occur along accessible floodplains, raising the groundwater table.  Although anecdotal evidence supports this process, few studies provide quantitative evidence of water table rise associated with beaver dam analogs. From 2006 to 2014 we monitored hourly water table elevation and temperature in two groundwater well fields on Bridge Creek, an incised tributary to the John Day River in northeastern, OR, USA. In 2009, BDA structures were installed to increase the number and lifespan of beaver dams adjacent to one well field, while the second well field remained untreated. Post-restoration monitoring measured larger increases in surface water extent at the BDA-treated well field and increased both the absolute and rate of water table rise relative to the untreated well field. In addition, groundwater and surface water temperature patterns became more similar post-restoration, suggesting increased aquifer recharge relative to before conditions.  Results suggest BDAs can be successfully utilized to raise groundwater tables and increase surface-groundwater exchange.

Groundwater Monitoring, Modeling, and Development in Response to the Military Buildup in Guam

Stephen Gingerich, Ph.D.
An expected significant population increase on Guam raised concern about the sustainability of groundwater resources. In response, the U.S. Geological Survey, in collaboration with the University of Guam’s Water and Environmental Research Institute of the Western Pacific and with funding from the U.S. Marine Corps, conducted a 3.5-year study to advance understanding of regional groundwater dynamics in the Northern Guam Lens Aquifer, provided a new estimate of groundwater recharge, and developed a numerical groundwater-flow and transport model for northern Guam. Results of the study, including three USGS reports, a scientific journal article, a well database, and an updated aquifer basement map provide more reliable evaluations of the potential effects of increased groundwater withdrawal and help guide sustainable management of this critical resource.

Two withdrawal scenarios (predevelopment conditions and a 5-year drought) indicated that prior to pumping, the freshwater lens was 10 to 50 feet thicker in the Yigo-Tumon basin and more than 50 feet thicker in the Hagåtña basin. The 2010 withdrawal distribution during a 5-year drought would result in decreased water levels, a thinner freshwater lens, and increased salinity of water pumped from wells. Available water with an acceptable salinity would decrease from about 34 million gallons per day to 11.5 million gallons per day after 5 years but recover to pre-drought levels 5 years after the return of average recharge conditions.

Five additional scenarios to assess groundwater demand projections and proposed new well sites under average and drought conditions indicated decreased water levels, a thinner freshwater lens, increased water salinity, and unacceptable salinity at several current withdrawal sites. However, some scenarios indicated that more than 40 million gallons per day can be withdrawn and the salinity of this water will remain in the acceptable category, except during drought.

Sustainability: The City of Pendleton Experience

Bob Patterson, PE
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Three Washington Cities with New Water Needs Using Shared Mitigation to Offset Impacts in Two Major Watersheds

Michael Gallagher, LHG
In December 2010, the City of Lacey submitted to Ecology a mitigation plan for six water right applications, from six different wells located in the Hawks Prairie and east Lacey area with a combined total of 7392 acre-feet per year (AFY) of new water.  Also in December 2010, the City of Olympia (jointly with the Nisqually Tribe) submitted a water right mitigation plan to transfer their 29,209 AFY of surface water rights from McAllister Springs to groundwater rights at a new “McAllister Wellfield”, located about 1.25 miles south of McAllister Springs.  In February 2011, the City of Yelm submitted a water right mitigation plan for one water right application totaling 942 AFY of new water.  Each water right application package had modeled impacts in the Nisqually and Deschutes Basins and McAllister, Woodland Creek and Yelm Creek Sub-basins.  Minimum instream flows in the Nisqually and Deschutes basins are protected by state regulation and are considered a water right.  

Olympia (and the Nisqually Tribe), Lacey and Yelm coordinated their efforts regarding future water supply needs for each entity.  All three cities used the same regional groundwater model and agreed to have their modeling consultants coordinate any changes with each other and to peer-review the model each time it was changed. 

In addition, the Cities combined their planning efforts and financial investment to propose a series of “water-for-water” and “out-of-kind” mitigation actions including recharging reclaimed wastewater and purchasing and retiring existing water rights and land purchases for riparian improvements to address modeled groundwater and surface water depletions that could be expected to occur in the Nisqually and Deschutes Basins and McAllister, Woodland Creek and Yelm Creek Sub-basins. Ecology also invoked the "Overriding Consideration of Public Interest" (OCPI) provision [RCW 90.54.020(3)(a)] since not all mitigation covered year-round pumping impacts from all of the new wells at full build-out.

During the winter and spring of 2012, Ecology approved and permitted Olympia’s water right changes from McAllister Springs to the new McAllister Wellfield and approved all of Lacey’s new water right applications.  Ecology also approved Yelm’s application for new water.  Yelm’s permit was appealed by a small group of local residents living near Yelm and this appeal (Foster v. Yelm) was elevated to the Washington State Supreme Court in May 2015.  In October 2015, the State Supreme Court ruled that Ecology exceeded its authority in issuing a new water right permit where all seasonal stream flow impacts were not offset with “water-for-water” mitigation.

Overall, joint mitigation efforts by neighboring cities or other public water supply entities can serve as a good example for how other municipalities and water systems can effectively and sustainably obtain new water for expected long-term growth in basins that have instream flow rules.  However, due to the October 2015 Washington State Supreme Court decision, only water-for-water mitigation can be used.  Thus the tools available for mitigation to offset future water uses by applicant for water rights in Washington is dramatically narrowed.

Using Aquifer Storage and Recovery in the Tualatin Basin to Provide Water Security to a Small Municipality

Robyn Cook, RG, PG, LG
The City of Cornelius, Oregon, has relied solely on water from the Tualatin River provided by the City of Hillsboro through the Joint Water Commission (JWC) to meet its drinking water demands. To meet future peak demands, the City initiated an exploratory drilling program to assess the feasibility of completing an aquifer storage and recovery (ASR) well within the Columbia River Basalt Group (CRBG) aquifer. In addition to meeting future peak demands, the City’s ASR program will provide a cost-effective way to store treated drinking water within the City and act as a critical facility. The City estimated that an aboveground storage tank would cost approximately $4 million to store 2 million gallons (MG), but a successful ASR well could store more than 50 MG for roughly $3 million.

In this small municipality, with a growing population and a changing climate, ASR will provide a cost-effective opportunity to use natural resources in a progressive and ecologically responsible manner. It is widely anticipated that warmer summers and declining snow packs will lead to diminished streamflows. By storing water during the winter, when precipitation and runoff are available, there will be less need to use valuable surface water during the summer months.

Using ASR to store water underground will provide the City with water security in the event of catastrophic dam or reservoir failures (which are a concern for the JWC’s Hagg Lake storage impoundment) that could result from a major subduction zone earthquake. Having an ASR program and an onsite generator will provide the City with a reliable backup water supply to meet the challenges of a growing municipality, including annual changes to the water cycle and the potential for catastrophic events.

Keynote Address — Climate Change and Water: Interconnections Within the Hydrologic Cycle

Diana Allen, Ph.D.

Surface Water/Groundwater Interaction

Yen-Vy Van, LHG

Evaluating the Role of Precipitation Pattern on the Temporal Changes in Streamflow and Baseflow

Zablon Adane
The Nebraska Department of Natural Resources has long been interested in assessing the long-term trends in streamflow and baseflow in major drainage areas across the state. One of the overall objectives of this effort is to examine the presence of temporal trends in precipitation and its impact on streamflow and baseflow. In order to isolate the impact of precipitation, a relatively undeveloped area in the Nebraska Sandhills was selected for this evaluation. Streamflow data for the Middle Loup River was obtained from USGS for the 1950 to 2014. Regional climate data at the Purdum, NE weather station was also provided by High Plains Climate Center (HPRCC) for the same time period. Simple linear regressions indicate an increasing trend in daily streamflow and baseflow over time. Meanwhile, the trend in daily precipitation is effectively zero. The regressions for the total annual values also indicate a robust positive trend in streamflow and baseflow. Further investigations show that the number of rainfall events have been steadily declining in the past few decades. A correlation matrix also reveals that streamflow has a stronger relationship with the number of rainfall events than with total precipitation. The declining number of wet days and the lack of trend in total rainfall suggest a potential increase in rainfall intensity, which could partially explain the increase in streamflow. It is important to note that other conditions that can increase streamflow, such as snowmelt rate, still need to be properly considered.

Hyporheic Cooling with Implications for Support of Fish Habitat in the Willamette Valley, Oregon

Bart Faulkner
It has been hypothesized that groundwater flow which originates from a river and then returns to it could result in a temperature buffering benefit, resulting from dissipation of heat during porous media flow. We installed 50 monitoring wells in a geomorphologically active area along the Willamette River in order to characterize wet and dry season hyporheic flow patterns. The wells were instrumented with pressure transducers with temperature logging, so that we could calibrate groundwater flow models. The sampling network was dense enough so that we could monitor the temperature and stable isotopic variation along individual groundwater pathlines. In one case we observed a temperature decrease of over 6 degrees Celsius along a distance of about 600 m, over a period of about 3 years. In observations along other pathlines we observed considerably lower temperature decreases, but still notable. This presentation will examine some of the possible mechanisms for the temperature decreases and the possible effect of seasonal shifts in flow vectors along hyporheic pathlines.

Parallelization and Linearization of Stream Depletion Analyses

Colby Osborn
The conventional numerical method of stream depletion analyses are often computationally demanding. This example demonstrates Nebraska’s Department of Natural Resources use of HTCondor and MODFLOW-SDA to parallelize and linearize the stream depletion analyses, respectively, to enormously reduce the computational time without deteriorating the accuracy in the conventional method. MODFLOW-SDA linearizes the flow equation in MODFLOW by assuming unchanged aquifer thickness within a time step period. MODFLOW-SDA is combined with HTCondor to compute the stream depletion distribution map in a parallel manner. Example results produced with this method applied are compared with results from the conventional method. The results compare favorably with those simulated using the conventional method, with significant improvement in computational efficiency. This method takes advantage of the existing computer resources within the Department and proves to be an effective solution for the high computational demands of stream depletion analyses.

Surface Water/Groundwater Interaction Between the Spokane River and SVRP Aquifer

John Covert, LHG
The 2015 drought in the Inland Northwest produced the hottest and driest summer on record in the Spokane area. The extremely low snowpack in the headwaters of the Spokane River resulted in the lowest daily average flow ever recorded in the Spokane River for the first few weeks of the summer, low flow season. The hydrograph for the summer months showed very little variability with no significant rain events and consistently low flows. The seven day low flow did not reach historic lows thanks to the 2009 FERC license issued to Avista for their dams on the Spokane River.

One consequence of the drought conditions was that Avista did not open the gates on their Post Falls dam on the Tuesday after Labor Day (which is the first day their FERC license allows them to begin drawing down the Lake Coeur d’Alene) like they do most years. In fact, they waited until mid-October to open the gates. This month-long delay in changing the flow regime in the Spokane River provided an opportunity for the hydraulics of the system to reveal an interaction between the Spokane River and the Spokane Valley Rathdrum Prairie Aquifer that had not been recognized in the 100+ years of streamflow data.

Data from the largest water purveyor in the aquifer suggests that summer pumping for all municipal uses from the aquifer was likely around 450 cfs in mid-August. As the daily maximum air temperature dropped near the end of August from the 95 oF range to 55 oF over a two week period, pumping stress on the aquifer started a month long decline. By the end of September, daily pumping from the aquifer likely dropped by 160 cfs. During the month of September, flows at the downstream gage on the Spokane River gradually climbed by 90 cfs while the flows at the upstream gage remained steady.

Continuous water level measurements collected at observation wells in the aquifer reveal a pronounced change in slope within a couple of days of the beginning of the break in groundwater pumping. The water table in the aquifer began rising at on August 29, 2015. 29 hours later, flow in the Spokane River began to rise.

A 160 cfs decrease in groundwater pumping from the aquifer resulted in a gradual increase in head in the aquifer of around half a foot over the month of September. This lead to a 90 cfs increase in discharge of water out of the aquifer and back into the river in the gaining reach.

This increase in discharge of groundwater back into the river must occur every year as the weather transitions from summer to fall conditions and groundwater pumping from the aquifer subsides. Normal river operations prevent us from seeing this gradual rebound in groundwater discharge. But the 2015 drought allowed us to see this surface water/groundwater relationship in the river flow for the first time in 100+ years of monitoring.

Understanding Effects of Groundwater Pumping on Streams in the Willamette Basin, Oregon

Nora Herrera
Limited streamflow during summer, a growing population, and agricultural needs are increasing the demand for groundwater in the Willamette Basin. Greater groundwater use could, however, diminish streamflow and create seasonal and long-term declines in groundwater levels. To better understand this problem, the U.S. Geological Survey (USGS) and the Oregon Water Resources Department (OWRD) cooperated to develop a conceptual and quantitative understanding of the groundwater-flow system of the Willamette Basin with an emphasis on the Central Willamette subbasin.

This cooperative study resulted in a final report that describes numerical models of the regional and local groundwater-flow systems and evaluates the effects of pumping on groundwater and surface-water resources. The models described can be used to evaluate spatial and temporal effects of pumping on groundwater, base flow, and stream capture.

The results from this study may be used to identify areas in the Willamette Basin where more data is needed to better understand groundwater and surface-water interactions. The scenarios in this study consider only changes in pumping as a cause of changes to groundwater levels, base flow, and stream capture. Other factors, such as climate change or changes in water-use patterns can also affect the hydrologic system. This study and the modeling tools it provides can be used as a starting point for climate and water-withdrawal optimization studies, water management and policy discussions, and strategies to help avert future water scarcity in the Willamette Basin.

Surface Water/Groundwater Interaction (cont.)

Erick Burns

Flow of Groundwater at the Interface with Permafrost

Sairavichand Paturi
Currently, the largest contaminated groundwater plume in Alaska exists in a discontinuous permafrost aquifer in the area of North Pole, Alaska. The aquifer is contaminated with sulfolane; a compound used in the refining of petroleum. As a part of remediation a relatively large monitoring well network has been installed to track the dispersion of the contaminant. Monitoring results revealed that the plume is much more dispersed in the lateral direction representing the contaminant presence in suprapermafrost and subpermafrost portions of the aquifer. Previous studies of this aquifer has shown that thawed through taliks exists in different areas of the plume providing connectivity between the sub and suprapermafrost portions of the aquifer. These taliks are providing the pathways for sulfolane to reach the subpermafrost portion of the aquifer and possibly retract into the suprapermafrost portion of the aquifer.

The objective of this study is to determine the pathway for sulfolane to reach the subpermafrost portion of the aquifer, we accomplished this goal by determining the vertical and horizontal flow gradients in key locations of the plume. Given the errors in water level measurements due to the frost heave and thaw settlement of monitoring wells indicates large measurement errors. Monte Carlo method is used to determine the asymmetrical errors. By reducing the measurement errors a three dimensional model with flow vector visualization of groundwater with discontinues permafrost has been created. The effect of seasonal variability in the flow pattern unleashed new understandings of the contamination plume boundary. With a precise flow vector visualization, seasonal variability and measured concentrations of sulfolane, a cutting-edge groundwater flow pattern in discontinuous permafrost regions has been determined. This is the fundamental study that has investigated groundwater flow at the interface with permafrost bodies in areas of discontinuous permafrost.  Understanding this interaction is key to our understanding of contaminant transport, aquifer recharge, and resource development in subarctic environments.

Hydrochemistry and the Flow System of Selected Geothermal Groundwater in Korea

Hanna Choi
Hydrochemical and isotope study has been conducted for three years to understand the flow system and changes of geothermal groundwater at four sites in Korea, which covers one coastal site and three inland sites. At each site, surface water and shallow groundwater were also sampled and the analytical results were compared with those of geothermal groundwaters.  

The coastal geothermal groundwater show the Na/Cl ratio about 0.48, seven times higher EC values and heavier isotope values ( 18O to 2.98‰, δ2H to 18.3‰) than shallow groundwater, indicating directing impact of sea water into the geothermal system. However, in the inland sampling sites, all the geothermal groundwater, shallow groundwater and surface water have similar 87Sr/86Sr ratio each other, implying that hydrochemistry of the those waters were formed by basically same water-rock interactions. Using the NETPATH program with the corrected 14C data, the circulation time of rainfall to geothermal groundwater were estimated to be from 2,000 to 5,700 years at the sites. The deeper the wells, the older the 14C age of groundwater. Hydrochemistry of deep geothermal groundwater in inland sites appear to be similar, but became diversified along the flow paths to the shallow groundwater system. Accounting for the age of waters and their hydrochemistry, it seems that the infiltrated rainfall forms shallow groundwater with diversified composition, and takes long time to become geothermal groundwater with strong water-rock reactions.

Surface Water/Groundwater Interaction Panel — The Work of Hydrogeologists: How and Where Do Practitioners Apply It?

Walter C. Burt, RG, LHG

Welcome

William Alley, Ph.D.