Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Halley_Barnett_2016

235 views

Published on

  • I am so pleased that I found you! I have suffered from Sleep Apnea for years. I have tried everything to fix the problem but nothing has worked. For the last years I have been trying to use a CPAP machine on and off but it is very difficult to sleep with. It's noisy and very uncomfortable. I had no idea there was a natural way to help me. I am so pleased that I found you!  http://t.cn/AigiN2V1
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Be the first to like this

Halley_Barnett_2016

  1. 1. GROUNDWATER DRAWDOWN IN HARNEY COUNTY, OREGON HALLEY BARNETT Submitted May 19, 2016 Completed in partial fulfillment of the Geoscience Major at Pacific Lutheran University
  2. 2. Barnett 1 ABSTRACT Groundwater in Harney County, Oregon is a significant source of water for this county that uses most of its land for agriculture and livestock. Water levels measured in wells have had several periods of decline in the past, and there is evidence that many of these water levels are currently in decline. The Oregon government needs to know if the current amount of water usage is sustainable in the long term. Data were synthesized to include well locations, water level measurements, peak flow values in the Silvies River, and maximum surface water right withdrawal. These data were used to evaluate spatial and temporal trends in groundwater with hydrographs and water elevation contour maps as well as the feasibility of continued surface water usage along the Silvies River. The majority of groundwater levels show a long-term downward trend. Surface water flow analysis of the Silvies River shows high annual variability, and a trend line of this data shows a slight upward trend over the past 109 years. Climate data shows a decrease in precipitation. This study provides a preliminary analysis of several components of the water budget in order to determine what future work needs to be done in this basin.
  3. 3. Barnett 2 TABLE OF CONTENTS ABSTRACT.................................................................................................................................... 1 INTRODUCTION .......................................................................................................................... 4 BACKGROUND ............................................................................................................................ 6 Geology....................................................................................................................................... 6 Hydrology and History................................................................................................................ 8 METHODS ................................................................................................................................... 10 Review and Compilation of Available Data Sources................................................................ 10 Analysis of Spatial Variation in Groundwater Levels. ............................................................. 11 Analysis of Temporal Variation in Groundwater Levels.......................................................... 11 Evaluation of Surface Water Resources.................................................................................... 12 Analysis of Total Annual Precipitation near Burns .................................................................. 13 RESULTS ..................................................................................................................................... 13 Well Locations and Data Distribution....................................................................................... 13 Hydrographs.............................................................................................................................. 13 Contour Maps of Water Elevations........................................................................................... 14 Surface Water Resources .......................................................................................................... 15 Precipitation .............................................................................................................................. 15 DISCUSSION............................................................................................................................... 15 Hydrographs and Temporal Changes in Water Levels ............................................................. 15 Contour Maps and Spatial Changes in Water Levels................................................................ 16 Surface Water Resources .......................................................................................................... 16 Well Locations and Data Distribution....................................................................................... 17 Precipitation, Groundwater, and Surface Water........................................................................ 18 Future Work .............................................................................................................................. 18 Groundwater Modeling. ............................................................................................................ 19 CONCLUSIONS........................................................................................................................... 21 ACKNOWLEDGEMENTS.......................................................................................................... 22 REFERENCES ............................................................................................................................. 23 FIGURES...................................................................................................................................... 27
  4. 4. Barnett 3 Figure 1: Study Location........................................................................................................... 27 Figure 2: Oregon Basins and Outlines. ..................................................................................... 28 Figure 3: Land Use in Harney County, Oregon. ....................................................................... 29 Figure 4: Simplified Geology of Harney County...................................................................... 30 Figure 5: Water Contours in 1931............................................................................................. 31 Figure 6: Study Area for GWR-16............................................................................................ 32 Figure 7: Hydrograph for a well drawing from deep valley fill................................................ 33 Figure 8: Digitized well locations in Harney County, Oregon ................................................. 34 Figure 9: TRSQQQ Well-Numbering System .......................................................................... 35 Figure 10: Water levels in an irrigation well............................................................................. 36 Figure 11: Hydrograph showing a downward trend over the past 15 years.............................. 37 Figure 12: Changes in water levels in 17 selected wells........................................................... 38 Figure 13: Decline vs. Increase in Water Levels. ..................................................................... 39 Figure 14: Water elevation contours for 1932 .......................................................................... 40 Figure 15: Water elevation contours for 2015 .......................................................................... 41 Figure 16: Satellite Imagery of Cone of Depression Location in 2015. This area shows agricultural development with no major visible streams flowing through to supply surface water.......................................................................................................................................... 42 Figure 17: Water elevation differences between 2011 and 2012.............................................. 43 Figure 18: Graph of peak flows for the Silvies River ............................................................... 44 Figure 19: Surface Water Availability. ..................................................................................... 45 Figure 20: Total Annual Precipitation near Burns, Oregon. ..................................................... 46 Figure 21: Mean Annual Flow in Silvies River. Data from: OWRD, Hydrographics, 2014.... 47 Figure 22: Preliminary MODFLOW model.............................................................................. 47 APPENDICES .............................................................................................................................. 48 Appendix 1: Wells Referenced ................................................................................................. 48
  5. 5. Barnett 4 INTRODUCTION Groundwater is an important resource for irrigation in America. Groundwater contributes about 43% of water used for irrigation worldwide and about 60% in the United States (Siebert et al., 2010). In order to use this important resource sustainably, long-term planning is needed due to the relatively slow rate of recharge compared to the average rate of withdrawal (Alley et al., 1999). In the Pacific Northwest, depletion of the Columbia River Basalt aquifer in Washington and Oregon have caused water levels to decline over 100 feet in some areas due to agricultural production (Burns, 1997). Some factors involved in the depletion of an aquifer include high pumping rates that withdraw more water than the aquifer can supply, rates of natural discharge through springs and streams that reduce the amount of water in the aquifer, and the physical properties of the aquifer (transmissivity, porosity, hydraulic conductivity, specific yield, etc.) (Bartolino and Cunningham, 2003). Other areas in the United States experiencing groundwater depletion include the Atlantic Coastal Plain, west-central Florida, the Gulf Coastal Plain, the High Plains, the Chicago-Milwaukee area, and the Desert Southwest (Bartolino and Cunningham, 2003). Some of the potential consequences of groundwater depletion include decreases in groundwater storage and water levels in wells, streams, and lakes (Alley et al., 1999). Other consequences may include loss of wetland and riparian ecosystems, land subsidence, saltwater intrusion, and decreased water quality (Alley et al., 1999). Groundwater depletion has become an ever-increasing issue in Harney County, which encompasses a region in southeastern Oregon (Figure 1, Figure 2) and covers an area of almost 6.5 million acres (U.S. Bureau of the Census, 271). Land is mainly used for agriculture and livestock (Figure 3). Between 1950 and 2012, the percentage of land used for agriculture in Harney County increased a total of 3.5 percent from 19.7 percent to 23.2 percent (U.S. Bureau of
  6. 6. Barnett 5 the Census, 271; U.S. Department of Agriculture, 230). In 2012, farmland in Harney County comprised 4.6 percent of the total farmland in Oregon, 1.3 times greater than the average amount of farmland for 28 counties (U.S. Department of Agriculture, 2014). The majority of land in this county is used to grow forage crops like hay, grass, and greenchop (U.S. Department of Agriculture, 2014). Because Harney County is such a significant agricultural producer, understanding of the sustainability of water resources in the county plays a vital role in determining future economic sustainability for both Harney County and Oregon as a whole. Due to a lack of current data, the Oregon Department of Geology and Mineral Industries (DOGAMI) is currently preparing for a basin-wide study in collaboration with the Oregon Water Resources Department (OWRD) (I. Gall, personal communication, May 26, 2015). Ivan Gall, the groundwater section manager at OWRD explains that the need for this type of study has increased since governor Kate Brown declared Oregon to be in a “drought emergency.” No new water rights will be issued in the county until more data has been collected in an attempt to slow the increasing rates of drawdown (Wing, 2015). The data collected for this research may be useful for part of this basin-wide study in understanding groundwater depletion and planning for future management of groundwater resources. Because agricultural development has been a vital part of the local economy, groundwater depletion would have a negative impact on financial success in this county. Can current agricultural practices be sustained, or do they need to be re-evaluated? This work attempts to identify and evaluate long-term spatial and temporal trends of groundwater depletion in Harney County by developing an understanding of groundwater resources. This will aid in determining how much agricultural production can be sustained with current agricultural
  7. 7. Barnett 6 practices. Due to reports of declining water levels in wells and the concern of the local government, it is likely that the current extent of groundwater use for agricultural production will need to be reduced in order to sustainably manage the basin’s groundwater supply either through a reduction in the amount of land used for agriculture or through the implementation of more efficient water-use practices. This research provides a qualitative analysis of trends in groundwater resources in comparison to groundwater use as well as an understanding of how agricultural development affects semiarid regions like Harney County. It could additionally be used as a scientific resource for water right analysis and for the formulation of new legislation as well as an understanding of how agricultural development affects semiarid regions. BACKGROUND Geology The area of Harney Basin in southeastern Oregon State is a semiarid region of about 5,300 square miles (Figure 1, Figure 2). It contains a central lowland area that lies generally between 4,080 feet and 4,095 feet in elevation above sea level which contains Malheur and Harney Lakes (Piper et al., 1939). This lowland area is an alluvial plain bounded by hills composed of volcanic and pyroclastic rocks and sediments (Leonard, 1970) and holds the majority of well data used in this study. The rest of the basin contains several cinder cones that have erupted and spread cinders and lava fields throughout the basin (Piper et al., 1939). The primary aquifers in the region include a shallow, unconsolidated valley fill with a thickness of up to 250 feet and deeper layers of permeable gravel, volcanic, and sedimentary layers interbedded with confining clay and tuff layers (Leonard, 1970).
  8. 8. Barnett 7 The Danforth formation of the Pliocene age lies in the upland in the northwestern part of the basin and ranges in thicknesses between 20 and 800 feet thick and is composed of layers of siltstone, sandstone, tuff, and volcanic ash as well as some lower layers of rhyolite (Piper et al., 1939). The Harney Formation, also of the Pliocene age, lies above the Danforth formation and mainly in the flat west-central portion of the basin and is a 750 foot thick deposit of basaltic tuff and breccia, sandstone, siltstone, water-bearing gravel, and scoria (Piper et al., 1939). The Quaternary formation lies in the southeastern portion of the basin, including some locations south of Malheur Lake, and is composed of pervious scoriaceous and fragmental volcanic material (Piper et al., 1939). Quaternary valley fill is comprised of alluvium, lake and playa deposits and eolian sediments weathered from upland volcanic rocks (Piper et al., 1939). Shallow valley fill holds unconfined alkaline water and the deeper valley fill holds confined water (Piper et al., 1939). Subsurface strata slope dips vary from 2° to 14° southward toward the center of the basin (Piper et al., 1939). A geologic map shows Harney County as being covered mainly by igneous rocks and clay (Figure 4). Aquifers in this county are made of sediments primarily derived from volcanic sources and allow for groundwater flow. Clay layers tend to form aquicludes, which restrict vertical groundwater flow and act as confining layers. As water flows into a confined aquifer, it reaches a point where it can no longer flow upwards and accumulates pressure. In an ideal scenario, as these confined aquifers are drilled into the pressure will cause the water to rise above the water table to an elevation referred to as the potentiometric head. The type of wells that draw from confined aquifers are often referred to as artesian wells. In creating water table contour maps for this study, all water levels are assumed to be water table measurements.
  9. 9. Barnett 8 Hydrology and History Harney County is a semiarid basin that receives rainfall during cold winters, with the wet season lying between November and February (Leonard, 1970). Mild summers receive ten percent of annual rainfall in the form of rare thundershowers (Leonard, 1970). Precipitation increases with altitude at the heads of major rivers (Leonard, 1970). Rainfall near Burns averages about 11 inches annually and averages about 8.8 inches nearer to Malheur Lake (Western Regional Climate Center, 2016; Leonard, 1970). Temperatures measured at Burns range from - 15 degrees Farenheit in January to 86 degrees Farenheit in July (Western Regional Climate Center, 2016). Groundwater recharge in the central lowland plains comes mainly from the adjacent uplands where water infiltrates into the ground through faults and fractures and from influent streams, and the main discharge of surface water from the basin is through evapotranspiration (Leonard, 1970). Groundwater tends to flow southeast (Figure 5) from recharge areas such as the more permeable alluvial fan near Burns and through the Silvies River losing water to the aquifers, to be discharged into Malheur and Harney Lakes (Piper et al., 1939; Leonard, 1970). Between the years 1930 and 1970, the water table elevation near the city of Hines decreased several feet and several wells and springs ceased to flow (Leonard, 1970). As people began to settle in Harney County in Eastern Oregon in the late nineteenth century, the demand for reliable information on water resources began to increase (Waring, 1909). In 1882 and again in 1901 and 1902, I. C. Russell began to collect data on the region. He concluded that Harney County is an artesian1 basin and that the most flowing water is likely to be found around the thermal springs located throughout the basin (Russell, 1903). He went on to 1 Artesian flow refers to water that flows out of a well without being pumped out. It usually occurs when the water is coming from a confined aquifer in which there is build-up pressure that forces the water upward through the well.
  10. 10. Barnett 9 postulate that there was plenty of water with deep artesian flows due to the greater depths needed to be drilled (Russell, 1903). G. A. Waring engaged in further reconnaissance in the area from 1906 to 1907, mapping the topography and land surface features to show relief and drainage. He talked to local ranchers and settlers to gain information on their water supplies, ending with the conclusion that the valley does not have storage adequate enough to produce a significant amount of flowing artesian wells. He also stated that there could be sufficient deep artesian flow along the southern border of the valley, but that it was not cost-effective to drill artesian wells (Waring, 1909). In 1939, the USGS published the most extensive and thorough study of Harney Basin that is still used as an important resource. The USGS, in cooperation with the Harney Branch Experiment Station, investigated geologic features and began compiling well logs and conducting regular water level measurements, chemical analyses, and pump tests. The authors concluded that there is not a large artesian head in the central plain of the basin, but some shallow water may be used for growing alfalfa (Piper et al., 1939). More of these data were collected for mostly newer wells in 1968 and was published in 1970 as Groundwater Report 16 by A.R. Leonard. This report expanded on the findings of the 1939 report and concluded that that there is still room for more development of the basin, but there is yet still a great deal of unpredictability in the amount and quality of water that will arise from drilled wells. They observed that the water table near Hines has declined since 1930 (Leonard, 1970), which could be a response to increased volumes of annual water withdrawals from wells resulting from increased development. The area studied in that report contains the most extensive data of the sources available for this study, and is thus the primary source of historical data for this report (Figure 6). The last study that has been published with a specific
  11. 11. Barnett 10 focus on Harney Valley was published in 1977. This report was published mainly to provide additional and updated data on wells and springs and did not produce any new conclusions (Gonthier et al., 1977). All other subsequent water-level datasets come from water supply papers reporting water levels for several western states and the original water level measurement sheets from the Oregon State Water Resources Department (OWRD). Hydrographs have been created for wells with recorded water levels (Figure 7). METHODS This study evaluates spatial and temporal trends in groundwater and uses modeling of drawdown in aquifers using graphical analyses and contour maps in ESRI’s ArcMap in order to develop an understanding of groundwater resources and depletion in Harney County, Oregon. The understanding of groundwater depletion will be useful in planning for long-term management of groundwater resources in Harney County and will provide a preliminary framework for future studies in the basin. Similar studies have been performed on the US High Plains and Californian Central Valley, in which spatiotemporal variations were quantified and used to determine the controls on depletion and to evaluate possible methods of reducing groundwater depletion (Scanlon et al., 2012). This research uses a similar approach in evaluating the water budget of the area and generates similar images depicting spatial and temporal trends in water levels. Review and Compilation of Available Data Sources. Data includes water levels, well locations (Figure 8), and well logs found in the Oregon Water Resources Department’s database. The database contains information compiled from
  12. 12. Barnett 11 published reports as well as water level data sheets used to record measurements taken by field staff and well logs filed by the driller. Calculations for water level measurements were checked for accuracy and correlated to well logs. Analysis of Spatial Variation in Groundwater Levels. Well locations and water levels were used to create water elevation contour maps for each year since 1930. Well locations were digitized as point locations in ESRI’s ArcMap based on either TRSQQQ locations (Figure 9) found in previous reports and well logs as well as USGS 7.5 minute topographic maps, satellite imagery, and GPS. Only wells associated with well logs and water levels were digitized due to time constraints and the nature of this study. The horizontal error for these wells lie between 25 and 3000 feet. Water levels were averaged from December through March of each water year to avoid the pumping season and establish yearly static water levels. The Spatial Analyst tool in ArcMap was then used to interpolate water elevation contour maps from water levels in wells that were both digitized in ArcMap and had static water levels associated with them. Analysis of Temporal Variation in Groundwater Levels. Water levels were taken from the Oregon Water Resource Department’s database. This database contains a digital compilation of water levels taken from USGS reports and field measurement sheets. Several contour maps created in the previous step were subtracted from each other using the Spatial Analyst tool in ESRI’s ArcMap to create water level difference contour maps. The pumping, rising, and flowing levels were removed in the creation of hydrographs to leave only static water levels reflecting the elevation of the water table. The wells selected for hydrographs all had more than five static water levels associated with them, less than
  13. 13. Barnett 12 twenty years between measurements, and had at least one measurement within the last fifteen years. There were seventeen wells that met these criteria. Well log numbers, water uses, depths, and locations of wells referenced in this paper can be found in Appendix 1. Hydrographs were made for selected wells showing trends in water elevations over time and were modified to appear on a single graph for comparative purposes. All water elevations for each well were converted to values reflecting the percent of the initial water elevation measured for that particular well in order to plot all wells on the same plot using the same axes. The wells were plotted together to reflect total water elevation changes for the basin and compare the amount of wells showing a decreasing water elevation to the amount of wells showing an increasing water elevation and the amount of wells remaining at a static water elevation. Evaluation of Surface Water Resources. The Silvies River runs through the area with the most groundwater data and flows by two of the three major cities in Harney County: Burns and Crane. This river has a gauging station upstream of these two cities which has data dating back to 1905. Peak flow values at gauging station 10393500 and surface water rights downstream from this station were taken from the Oregon Water Resources database in order to determine if there were any years during which surface water users never received the maximum amount of water they were legally allowed to use. These downstream surface water rights were identified by spatial location between the gauging station and Malheur Lake and attribute data specifying that the water assigned to the water rights came from the Silvies River using ESRI’s ArcMap. The maximum rates (in cubic feet per second) issued to each of the surface water users downstream of the gauging station were added together and compared to the maximum rate (in cubic feet per second) flowing from the upstream gauging station. This method greatly simplifies the Silvies River system and does not
  14. 14. Barnett 13 account for all of the different branches of the river, instead focusing on the main branches along which water users obtain their water. Analysis of Total Annual Precipitation near Burns Yearly precipitation totals for two sites near Burns, Oregon were used to create a graph of total annual precipitation over time. These sites were chosen from among a small selection of available data because they lie within the area with the greatest concentration of data and land development (Figure 8). Measurements from 1939 through 1979 were taken at the Burns Federal Building and measurements from 1980 through 2015 were taken at the Burns Municipal Airport. RESULTS Well Locations and Data Distribution Well locations are concentrated more in the northern portion of Harney County, near to cities and water sources (Figure 8). These lands show the most agricultural development lie around the three major cities in the county: Burns, Hines, and Crane. Major surface water features include the Silvies River, which drains into Malheur, Mud, and Harney Lakes. Hydrographs Several hydrographs in irrigation wells show general downward trends in water levels over time on the multi-decadal scale. A clear example of this trend would be HARN 130, which is a well drawing from deep valley fill (Figure 7). The water levels in this well show seasonal variations, but there is an overall downward trend between the years of 1930 and 1990. A similar well, HARN 547, is an artesian well drawing from deep valley fill (OWRD, 2015). This well shows several large drawdowns in several summers in the 1930’s, then maintains a relatively
  15. 15. Barnett 14 stable range of water levels with small seasonal variations until the 2000’s (Figure 10). Beginning in about 2003, water levels in HARN 547 began a downward trend with greater seasonal variability than it had in the previous few decades (Figure 11). Water level measurements for seventeen selected wells were plotted together on a graph showing percentages of initial water level for comparative purposes (Figure 12). The percentages that are less than one hundred show a decline in water levels and the percentages that are more than one hundred show an increase. Percentages of one hundred show no change in water level from the initial measurement. The largest drop in water levels was a drop of 1.2% of the initial measurement, whereas the largest increase was 0.3% of the initial measurement. Contour Maps of Water Elevations Water level contours for 1932 confirm the established assumption that groundwater flows southeastward toward Malheur Lake due to the steady decline in water levels toward the southeast2 (Figure 14). The most recent water level contours maintain the southeastward direction of groundwater flow, but also establish an area of localized drawdown that causes the groundwater to flow southwest, forming a cone of depression3 just north of Harney Lake (Figure 15). Satellite imagery of this localized cone of depression was also analyzed (Figure 16). On a larger scale, recent water level contour differences for the central part of the basin also show downward trends in most of the county, especially in the south-central portion of the basin and some localized areas in the north-central region (Figure 17). The cone of depression that was visible in the 2015 water table contours shows a decline in water levels between 2011 and 2012, with the center of the cone declining faster than the edges. 2 Groundwater flows from areas of high head (high water elevation) to low head (low water elevation). 3 A cone of depression is an area of low head due to localized drawdown of the water table. The top of the water table plunges toward the low point on all sides, forming a cone.
  16. 16. Barnett 15 Surface Water Resources Peak flow values for the Silvies River were graphed for the period of time between 1905 and 2015. Despite high annual variability, a linear trend line shows a very slight upward trend (Figure 18). However, the error for this trend line is high enough to render the supposed increase insignificant. The maximum flow value for the entire period was a value of 4,960 cubic feet per second, and the minimum peak flow value was 75 cubic feet per second. Throughout the entire 110 year period, there was only one year (1933) during which the surface water users never had enough to use the maximum amount of water ascribed to them (Figure 19). Precipitation Total annual precipitation near Burns since 1939 ranges from 4.67 to 18.24 inches. A linear best fit line shows a long-term downward trend in annual precipitation (Figure 20). DISCUSSION Hydrographs and Temporal Changes in Water Levels The greater portion of the water level data points on Figure 12 show a decline throughout the past eighty-five years, which suggests that more of the water levels are declining than increasing. Moreover, the greater range of declining values as compared to the range of increasing values indicate greater potential for declining water levels (Figure 13). There appear to be some major water level declines in the 1930’s, the 1970’sthe 1990’s, and around 2010 for the majority of selected wells (Figure 12). These could be correlated with either drought or increased water withdrawals. Not all wells show drawdown over time. Because they do not fit
  17. 17. Barnett 16 the trend of the majority, it could be that these wells are drawing from different aquifers that either have more water or are not being used as much as the other aquifers. Contour Maps and Spatial Changes in Water Levels A cone of depression is a localized drop in water table elevation, with groundwater flowing downward toward the center of the cone. If rates of groundwater withdrawal exceed the rate of aquifer recharge from streams and infiltration from upland areas, then a cone of depression forms around the well or wells involved. Historical groundwater elevation contours show that groundwater was flowing southeast in the lowland area just north of Malheur and Harney Lakes (Figure 14). But more current contour maps show a large cone of depression just north of Harney Lake. This may be due to overexploitation of the aquifer because the localized drawdown appears in the form of a cone of depression that is characteristic of pumping. For the 2015 contour map, this cone interrupts the mostly parallel gradient of contour lines established in 1932, causing the groundwater to change trajectory toward the southwest (Figure 15). Satellite imagery of this localized cone of depression reveals that this is an area of agricultural development and irrigation with little to no available surface water (Figure 16). There are nearby lakes, but it does not appear that any water from the lakes is being diverted to these fields. Surface Water Resources This study greatly simplified the surface water system for the purposes of evaluating overall qualitative trends in more densely populated areas. The Silvies River is a meandering river with several branches and calculated downstream flow values do not take into account branching in the stream or any variations in flow velocity between the measurement point at station 10393500 and points of surface water diversion. Amount of water withdrawn was assumed to be the maximum amount allowed by the Water Resources Department.
  18. 18. Barnett 17 Peak flow values were used in determining if there is enough water for water users drawing water from the Silvies River. Because there was only one year in the past 110 years in which these surface water users did not have enough water to draw their allotted water, it is likely that the water from the Silvies River has not been over-allocated. It is important to note that because there is such high annual variability in peak flow values for the Silvies River, it is difficult to establish a trend using this type of data. This study aims to establish long-term trends on the multi-decadal scale, but surface water data shows great variability and it is therefore difficult to establish a reliable trend. With a very low R2 value, the linear trend line fit to the data shows a very slight upward trend in peak flow (Figure 18). In order to further determine the validity of the slight upward trend found in peak values, mean annual flow values were plotted as well (Figure 21). The linear trend line fit to this data has a much higher R2 value and also shows an upward trend in surface water flow in the Silvies River. With the higher R2 value and lesser amount of annual variability, these mean annual flow values show a more clear picture of the upward trend in surface water flow. Well Locations and Data Distribution Because data are mostly concentrated in the lowland areas in the central northern portion of Harney County around Malheur and Harney Lakes where there is the most development and these wells show a distinct downward trend in water levels, it may be possible to hypothesize that these declining trends may correlate with development, however; data from unused wells outside these inhabited areas within the lowland area would be needed to further explore any possible connection.
  19. 19. Barnett 18 Precipitation, Groundwater, and Surface Water The majority of wells show a decrease in water levels and a high potential for water level decline. Precipitation also shows a long-term downward trend. Since aquifer recharge in the central lowland area comes mainly from infiltration from precipitation in the surrounding uplands, this decrease in precipitation could be showing a decrease in recharge rates of the aquifer. If the rate of recharge decreases, then the water table or potentiometric head reflected in wells should drop. The increase in surface water flow in the Silvies River was surprising because the amount of precipitation and water levels have been declining. A possible hypothesis would be that groundwater withdrawals have been increasing, but not all of the water was used and instead flowed into the stream as runoff. Future Work This study was intended to provide a broad view of the spatiotemporal trends in water resources in Harney County, Oregon with a primary focus on changes in groundwater elevations. A more in-depth analysis of the water resources in this area would involve an analysis of the full water budget, including evapotranspiration, precipitation, infiltration, and groundwater recharge, discharge, and storage. This analysis may include spatial and temporal variation. More monitoring wells could be drilled to increase the amount of current data available for the basin and pump tests can be conducted to test aquifer properties like porosity, permeability, storativity, and hydraulic conductivity. There is some pump test data available for this county, but it is not available online and has not yet been checked for quality. It has already been postulated that irrigation runoff from groundwater sources has been increasing the amount of surface water flow over time. The next step would be to analyze the interaction between groundwater and surface water. This can be done by placing monitoring
  20. 20. Barnett 19 wells by streams and monitor water levels in the wells and stream stage in the streams. Contour maps of the water table could include lake levels and stream stages to further evaluate the relationship between surface and ground water. The presence of the large cone of depression north of Harney Lake could have far- reaching negative implications on groundwater resources and should be investigated further. Irrigation and water use practices may need to be analyzed to determine how efficiently the water is being used. Due to the inconsistency of pump test data, it may be possible to use water levels reflecting this cone of depression over time and water use data to evaluate aquifer characteristics, or new pump tests may be conducted. Water level contours for each year may also be compared to determine when the cone began to be formed and what other events (e.g. the drilling of new wells) may correlate with this formation. Discharge from wells and streams are an important part of analyzing the water budget in Harney County and can be evaluated with water usage and water right data. Currently, data defining the amount of water used is difficult to access and would need to be compiled before analysis. This study focused on water resources used for irrigation, but further study could include an evaluation of habitat extent and water resources available for wildlife in this basin. Groundwater Modeling. In analyzing the water budget and groundwater flow in a basin, it is often useful to create a model to account for all of the different factors involved. Such a model can also be used to project future scenarios while taking into account multiple variables. This study suggests the use of a program called MODFLOW-2005, which is a finite-difference groundwater model that uses a block-centered finite-difference simulation of groundwater flow and associat external stresses such as wells, recharge, evapotranspiration, discharge, and streams to incorporate all aspects of
  21. 21. Barnett 20 the water budget into a single comprehensive model (Harbaugh, 2005). The program also allows for diffent hydrologic features to be analyzed both separately and together to provide a flexible framework building a model (Harbaugh, 2005). In order to attempt to reproduce the past changes in the water table and project water table elevations into the future, a simple groundwater framework model was created using MODFLOW-2005 in the graphical user interface called ModelMuse. This model was the original goal of this study, but the extent of data compilation and analysis that was required prior to building the model revealed that such a model was not yet feasible. An initial attempt at creating a model is shown in Figure 22. Proper validation of this preliminary model will require significant future work to increase the resolution of the inputs. The procedures used in creating this model are outlined below. Wells were selected based on period and consistency of record, proximity to other wells, and quality of data. After placing these constraints on the data available, four wells south of Malheur and Harney Lakes were identified as having the most accurate data at as small a scale as possible. The wells selected have the well log identification numbers HARN 1387, HARN 1393, HARN 1408, and HARN 1477. A rectangle was drawn around the wells in ArcMap, and the shapefiles of the wells, the rectangle, and Malheur Lake were imported into ModelMuse. A grid was drawn over the rectangle and the rectangle was deleted. The lake shape was adjusted to fit within the grid. The subsurface was simplified to one aquifer layer to reflect water-bearing layers present in the well logs and was expanded to a depth of 200 feet to include the entire extent of the deepest well. A transmissivity value of 1000 ft2 /day was input to represent an aquifer composed of cinders. Lake and well water levels were also inputted before running the model. Water levels
  22. 22. Barnett 21 in each of these wells were averaged for every five-year period to further simplify the data. The model parameters were then adjusted as needed to improve accuracy. This model can only be used as a qualitative analysis of the water table in the area south of Malheur and Harney Lakes and lacks the accuracy needed for a sufficient quantitative analysis. Factors not included in the model include changes in lake water levels, precipitation and infiltration, pumping rates and amounts, and multiple layers within the subsurface. The model results show current water level contours that indicate that groundwater south of Malheur Lake flows southwest away from the lake from areas of higher head to areas of lower head (Figure 22). Further inputs are required to project the model into the future. The model shows a localized high water elevation in the southwestern portion of the grid near HARN 1098, which is not consistent with the actual measured water elevations. It is unclear at this time what is causing this inconsistency. CONCLUSIONS Groundwater resources in in the lowland area north of Malheur and Harney Lakes appear to be diminishing as evidenced by significant proportions of wells that have been experiencing declining water levels. Recent groundwater elevation contours show a large cone of depression around a group of fields just north of Harney Lake that interrupts the historical pattern of southeastward groundwater flow. These agricultural fields appear to be using exclusively groundwater sources for irrigation and may be playing a part in the localized drawdown and creation of the cone of depression. Two different datasets showing an upward trend in surface water flow. Peak flow values in the Silvies River measured near Burns, Oregon show a great range of annual variability. A
  23. 23. Barnett 22 linear trend line fitted to this data shows a slight upward trend, but does not have a high degree of reliability. Mean annual flow values, however, show greater reliability in a similar upward trend, with a higherR2 value. Because groundwater levels are mainly decreasing and precipitation shows a decreasing trend over time, it is possible that groundwater is being withdrawn at a rate that exceeds recharge, but not all the water is being used and is instead running off into the surface water system. There is still a lack of the data required to perform a full analysis of the water budget in Harney County, but this study provides an initial overview of long-term trends in precipitation and surface water and spatiotemporal trends in groundwater. Future work will include climate and groundwater pumping data, identification of aquifers being used by each well, and more thorough evaluation of surface water usage and flow values. Future work could also make use of MODFLOW-2005 to create a comprehensive model of groundwater flow while taking into account multiple parts of the water budget in the basin. Preliminary modeling efforts reveal that more research is needed before creating a comprehensive model of the basin. But the work done in this study, including the identification of several long-term trends in surface water, precipitation, and groundwater as well as discovery of a cone of depression just north of Harney Lake provide a starting point for future work. ACKNOWLEDGEMENTS A special thank-you to the Oregon Water Resources Department and the U.S. Geological Survey for providing data for this study as well as to the Department of Geosciences at Pacific Lutheran University for providing resources for me to be able to complete this project. Thank you to my family, friends, professors, and peers for supporting me throughout this process.
  24. 24. Barnett 23 REFERENCES Alley, W. M., Reilly, T. E., and Franke, O. L. (1999). “Sustainability of Ground-Water Resources.” U.S. Geological Survey. Circular 1186. Bartolino, J. R. and Cunningham, W. L. (2003). “Ground-Water Depletion Across the Nation.” U.S. Geological Survey. Fact Sheet 103-03. Burns, A. W. (1997). “Ground-Water Resources in the Western United States: Sustainability and Trends.” In “Western Water Policy Review Council, Water for the West: The Challenge for the Next Century,” Public Review Draft (1997): 2.10-2.16. ESRI, State, ESRI, 2011. ESRI, Counties, ESRI, 2008. ESRI, City_ply, 1:500,000 to 1:5,000, ESRI, 2011. Gonthier, J. B., Collins, C.A., and Anderson, D.B. (1977). “Ground-Water Data for the Drewsey Resource Area, Harney and Malheur Counties, Oregon.” U.S. Geological Survey. Open- File Report 77-741. Harbaugh, A. W. (2005). “MODFLOW-2005, The U.S. Geological Survey Modular Ground- Water Model—the Ground-Water Flow Process.” U.S. Geological Survey. Techniques and Methods 6-A16. Leonard, A. R. (1970). “Ground-Water Resources in Harney Valley, Harney County, Oregon.” U.S. Geological Survey. Ground Water Report No. 16. NAIP, Framework Imagery Orthoimagery Aerial 2011 ImageryFramework, USDA Farm Service Agency, Oregon NavigatOR Program, Oregon Geospatial Enterprise Office, October 4, 2011.
  25. 25. Barnett 24 Oregon Public Broadcasting (2016). “New Armed Group Enters Harney County, Meets with Sheriff.” opb.org. Accessed May 3, 2016. < http://www.opb.org/news/series/burns- oregon-standoff-bundy-militia-news-updates/armed-convoy-arrives-at-harney-county- courthouse/>. Oregon Water Resources Department. “Hydrographics Data Access and Summary Statistics.” WRD.state.or.us, September 30, 2014. Accessed January 14, 2016. <http://apps.wrd.state.or.us/apps/sw/hydro_report/gage_data_request.aspx?station_nbr=1 0393500>. Oregon Water Resources Department. “Water Right Data/GIS Themes.” Oregon.gov, 2014. Accessed January 15, 2016. <http://www.oregon.gov/owrd/Pages/maps/index.aspx#Water_Right_Data/GIS_Themes> Oregon Water Resources Department. “Water Level Data and Hydrographs.” Oregon.gov, 2015. Accessed January 13, 2016. <http://www.oregon.gov/owrd/pages/gw/well_data.aspx>. Oregon Water Resources Department. “Well Log Query.” Oregon.gov, 2016. Accessed January 14, 2016. < http://apps.wrd.state.or.us/apps/gw/well_log/>. Oregon Watershed Enhancement Board. “OWEB Small Grant Areas.” Oregon.gov/OWEB, 2007. Accessed May 9, 2016. <http://www.oregon.gov/OWEB/GRANTS/PublishingImages/smallgrantteams_im.jpg>. Piper, A. M., Robinson, T. W., and Park, C. F. Jr. (1939). “Geology and Ground-Water Resources of the Harney Basin, Oregon.” United States Department of the Interior, Geological Survey. Water-Supply Paper 841.
  26. 26. Barnett 25 Russell, I. C. (1903). “Preliminary Report on Artesian Basins in Southwestern Idaho and Southeastern Oregon.” United States Geological Survey. Water-Supply and Irrigation Paper No. 78. Scanlon, B. R., Faunt, C. C., Longuevergne, L., Reedy, R. C., Alley, W. M., McGuire, V. L., & McMahon, P. B. (2012). “Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley.” Proceedings of the National Academy of Sciences of the United States Of America, 109 (24), 9320-9325. doi:10.1073/pnas.1200311109 Siebert, S.; Burke, J.; Faures, J. M.; Frenken, K.; Hoogeveen, J.; Dӧll, P.; and Portmann, F.T. (2010). “Groundwater Use for Irrigation – A Global Inventory.” Hydrology and Earth System Sciences 14: 1863- 1880. U.S. Bureau of the Census (1952). “United States Census of Agriculture: 1950: Counties and State Economic Areas: Washington and Oregon.” U.S. Bureau of the Census. Volume 1, Economic Areas, Part 32. U.S. Department of Agriculture (2014). “2012 Census of Agriculture.” U.S. Department of Agriculture. Volume 1, Geographic Area Series, Part 37. USGS, Geology of Oregon – USA. USGS, March 14, 2016. Accessed April 14, 2016. < https://mrdata.usgs.gov/geology/state/state.php?state=OR>. USGS, Land –Use, Scales less than 1:250,000, USGS, March 5, 2014. Accessed January 15, 2016. < http://water.usgs.gov/GIS/dsdl/ds240/>. Waring, G. A. (1909). “Geology and Water Resources of the Harney Basin Region, Oregon.” United States Geological Survey. Water Supply Paper 231.
  27. 27. Barnett 26 Wing, S. V. (June 30, 2015). “No New Wells in Harney County.” Oregon Public Broadcasting. http://www.opb.org/radio/programs/thinkoutloud/segment/no-new-wells-in-harney- county/ [Accessed October 26, 2015]. Western Regional Climate Center (2016). “Burns Federal BLDG, OR: Monthly Average of Average Daily Temperature (Degrees Fahrenheit).” WRCC.DRI.edu. Accessed May 3, 2016. http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?or1176>. Western Regional Climate Center (2016). “Burns Federal BLDG, OR: Monthly Sum of Precipitation (Inches).” WRCC.DRI.edu. Accessed May 3, 2016. < http://www.wrcc.dri.edu/cgi- bin/cliMAIN.pl?or1176>. Western Regional Climate Center (2016). “Burns Muni AP, OR: Monthly Average of Average Daily Temperature (Degrees Fahrenheit).” WRC.DRI.edu. Accessed May 3, 2016. <http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?or1175>. Western Regional Climate Center (2016). “Burns Muni AP, OR: Monthly Sum of Precipitation (Inches).” WRCC.DRI.edu. Accessed May 3, 2016. < http://www.wrcc.dri.edu/cgi- bin/cliMAIN.pl?or1175>.
  28. 28. Barnett 27 FIGURES Figure 1: Study Location. This map shows Oregon state, with counties outlined in black. Harney County is filled in with red.
  29. 29. Barnett 28 Figure 2: Oregon Basins and Outlines. Harney County lies on top of the Malheur Lake Basin (in purple, number 22 on this map). Modified from OWEB, 2007.
  30. 30. Barnett 29 Figure 3: Land Use in Harney County, Oregon. The majority of the county is made up of mixed rangeland and cropland.
  31. 31. Barnett 30 Figure 4: Simplified Geology of Harney County. The majority of the basin is covered in igneous rocks and clay. Geology of Harney County
  32. 32. Barnett 31 Figure 5: Water Contours in 1931. Water elevation contours for wells drawing from deep valley fill in the northwestern lobe of the central alluvial plain in Harney County, Oregon (Piper et al., 1939). Solid lines represent contours for August 3, 1931 with a two-foot contour interval. Dashed lines represent contours for May 11-15, 1931 with a five-foot contour interval. There are two distinct cones of depression in Township 23S, Range 32E, between the cities of Burns and Harney, which are indicated by blue dots. Direction of groundwater flow is indicated by blue arrows. Modified from: Piper et al., 1939. Burns Harney 1931 Groundwater Flow
  33. 33. Barnett 32 Figure 6: Study Area for GWR-16. The area lies just north of Malheur Lake in the northern central portion of Harney County. This area contains the most extensive groundwater data. Modified from: Leaonard, 1970.
  34. 34. Barnett 33 Figure 7: Hydrograph for a well drawing from deep valley fill. Measurements shown were taken when water levels were static and not rising or falling. Water levels show seasonal variations and an overall downward trend from 1930 to 1990. This well is identified by its well log number: HARN 130. Modified from OWRD, “Hydrographics,” 2014. WaterLevel(feetbelowlandsurface) Year 0 5 10 15 20 25 30 1930 1940 1950 1960 1970 1980 1990 2000 Change in Water Levels in HARN 130
  35. 35. Barnett 34 Figure 8: Digitized well locations in Harney County, Oregon. The greatest groupings of wells are located near cities and water sources. Burns Hines Crane
  36. 36. Barnett 35 Figure 9: TRSQQQ Well-Numbering System used in locating wells in Oregon. This coordinate system splits the state into a grid of Townships and Ranges. Townships run north-south and ranges run east-west. Each township-range grid cell is further split into sections, numbered one through thirty-six. Each section is broken into quarters referred to as a, b, c, and d. Each quarter can be further split into quarters, which can again be split into more quarters. This method was used by surveyors in the field to be able to record locations. Many of the wells on file are associated with a TRSQQQ location, which were converted into latitude/longitude coordinates for the purposes of this study with some degree of horizontal error measuring up to 1,000 feet. Figure from Gonthier et al., 1977. Well Numbering System
  37. 37. Barnett 36 Figure 10: Water levels in an irrigation well graphed as percent of the initial measured value. There are several large dips in the water levels for several summers, indicating either droughts, drier summers, or increased pumping. These dips could indicate pump tests as this well was formerly owned by the Harney Branch Experiment Stations, which conducted multiple tests on wells. For the majority of the 87 year time period, the water levels have remained relatively stable over the long term with high potential for water level decrease and a lower potential for water level increase above the initial head. Data from: OWRD, 2015. 98.4 98.6 98.8 99 99.2 99.4 99.6 99.8 100 100.2 100.4 1928 1942 1956 1969 1983 1997 2010 PercentofInitialValue Year HARN 547 Water Levels
  38. 38. Barnett 37 Figure 11: Hydrograph showing a downward trend over the past 15 years in water levels for an irrigation well, plotted as percent of initial value measured in 1928. y = -0.0001x + 103.85 R² = 0.24 98.8 99 99.2 99.4 99.6 99.8 100 100.2 2000 2002 2005 2008 2010 2013 2016 PercentofInitialValue Date HARN 547 Water Levels for the Past 15 Years
  39. 39. Barnett 38 Figure 12: Changes in water levels in 17 selected wells over time as percentages of initial water levels in wells containing five or more static water level measurements in Harney County. 98 98.5 99 99.5 100 100.5 1928 1942 1956 1969 1983 1997 2010 PercentofInitialHead Year Comparison of Water Levels in 17 Selected Wells
  40. 40. Barnett 39 Figure 13: Decline vs. Increase in Water Levels. The largest increase in water level percent was 0.3%, and the largest decrease was 1.62%.
  41. 41. Barnett 40 Figure 14: Water elevation contours for 1932 at ten foot intervals based on available data for this time period. Harney County lies within Malheur Lake Basin, which is denoted by the blue outline.
  42. 42. Barnett 41 Figure 15: Water elevation contours for 2015 at ten foot intervals based on available data for this time period. Harney County lies within Malheur Lake Basin, which is denoted by the blue outline. Cone of Depression
  43. 43. Barnett 42 Figure 16: Satellite Imagery of Cone of Depression Location in 2015. This area shows agricultural development with no major visible streams flowing through to supply surface water. Satellite Imagery of Cone of Depression 2015
  44. 44. Barnett 43 Figure 17: Water elevation differences between 2011 and 2012 in Malheur Lake Basin. Red indicates a decrease in water elevation and blue indicates an increase in water elevation. Contour interval is one foot. Cone of Depression
  45. 45. Barnett 44 Figure 18: Graph of peak flows for the Silvies River in cubic feet per second measured at gauging station 10393500 (OWRD, 2014). y = 0.2226x + 1006.4 R² = 5E-05 0 1000 2000 3000 4000 5000 1905 1925 1945 1965 1985 2005 PeakFlow(cubicfeetpersecond) Year Peak Flow by Year 75 4,960
  46. 46. Barnett 45 Figure 19: Surface Water Availability. Water withdrawal locations are grouped into three groups of upstream, study area, and downstream. For the year of the lowest peak flow (1933), there is not enough water in the Silvies River to satisfy downstream water users. For the year of the highest peak flow (1952), there is plenty of water for all water users drawing water from the Silvies River. I created the river and study location shapes using aerial imagery.
  47. 47. Barnett 46 Figure 20: Total Annual Precipitation near Burns, Oregon. A linear trend line shows a long-term downward trend in annual precipitation. Data from Western Regional Climate Center, 2016. y = -0.0256x + 61.61 R² = 0.0378 4 6 8 10 12 14 16 18 1939 1949 1959 1969 1979 1989 1999 2009 TotalAnnualPrecipitation (inches) Year Total Annual Precipitation near Burns, Oregon
  48. 48. Barnett 47 Figure 21: Mean Annual Flow in Silvies River. Data from: OWRD, Hydrographics, 2014. Figure 22: Preliminary MODFLOW model. Contours shown are water elevations in 2015 with one foot contour intervals. The red indicates higher water levels, and blue indicates lower water levels. y = 0.6885x - 1173 R² = 0.0278 0 100 200 300 400 500 600 1904 1924 1944 1964 1984 2004 MeanAnnualFlow(cfs) Year Mean Annual Flow in Silvies River
  49. 49. Barnett 48 APPENDICES Appendix 1: Wells Referenced in this paper. Pink and blue cells represent wells that were part of the seventeen selected wells used in creating Figure 12. Blue cells represent wells which were also selected for creating the MODFLOW model due to their proximity to each other. Well Log Number Use Depth (feet) Location HARN 130 Unknown 288 22S/31E-34cc HARN 198 Irrigation 260 22S/32.5E-26ab HARN 219 Irrigation 835 22S/33E-27J(1) HARN 323 Irrigation 198 23S/30E-36cbc HARN 440 Irrigation 120 23S/31E-11Q(1) HARN 441 Irrigation 561 23S/31E-11Q(2) HARN 463 Not used 300 23S/31E-16NWSE HARN 547 Irrigation 93 23S/32E-7L(2) HARN 607 Irrigation 240 23S/32E-29H(1) HARN 741 Irrigation 207 23S/34E-31SENE HARN 813 Irrigation 347 24S/30E-7SESW HARN 1065 Irrigation 85 24S/34E-31bb HARN 1245 Irrigation 160 25S/34E-6bb HARN 1363 Irrigation 147 26S/31E-34R(1) HARN 1387 Irrigation 105 26S/33E-13J(1) HARN 1393 Irrigation 97 26S/33E-19R(1) HARN 1408 Irrigation 81 26S/33E-34N(2) HARN 1477 Irrigation 176 27S/33E-2D(1) HARN 1990 Irrigation 100 25S/30E-27cd

×