H31H-01 INVITED
Overview of Hydrologic Issues in the Upper Klamath River Basin, Oregon
The geologic setting of the upper Klamath Basin makes it a naturally arid landscape with eutrophic water bodies. Anthropogenic alterations of the land and hydrology over the past 100 years have put large demands on water supplies and further enriched water bodies with nutrients. Major changes to the upper basin include diking and draining lakes and wetlands for agricultural and grazing land, modifying lakes to increase the supply of summer irrigation water, clearing land and harvesting timber, and installing hydropower dams on the mainstem Klamath River that has blocked salmon passage above Iron Gate Dam. These alterations have contributed to diminished populations of endangered shortnose and Lost River suckers in the upper basin and threatened Coho salmon in the lower Klamath River. Upper Klamath Lake (UKL), with an average depth of 2.5 meters and a surface area of 310 square kilometers, is the primary water-supply reservoir for the Bureau of Reclamation's Klamath Project, which services about half (97,000 ha) of the irrigated agriculture in the upper Klamath Basin. The lake is also the primary habitat for the two endangered suckers. Because of the nutrient enrichment of UKL, the development of large summer blooms of Aphanizomenon flos-aquae, and the periodic crash of these near monoculture blooms, the magnitude and frequency of large sucker die-offs from hypoxia have increased. The relation between management of the lake and surrounding wetlands and algal ecology is not well understood. It is clear, however, that runoff from drained wetlands upstream and around UKL have enriched the lake water and its bottom sediments with phosphorus for many decades. Internal loading from enriched bottom sediments triples the summer phosphorus concentration in UKL and fuels the problematic algal blooms from June through October. An ongoing pattern of below-average precipitation has increased demands from UKL and generated concern. Two recent Biological Opinions aimed at protecting threatened and endangered fish call simultaneously for downstream water deliveries from UKL to provide salmon habitat while maintaining water levels in UKL for shoreline spawning and rearing of suckers. These demands cannot be met during extended droughts if full water deliveries are made to farms and several National Wildlife Refuges. Attempts to increase water supplies through land idling, increased ground-water pumping, and conservation have met with mixed success. The hydrologic issues surrounding the water controversy in the upper Klamath Basin will be expanded upon in this presentation along with an introduction to some of the past, ongoing, and future studies aimed at bringing science and data to the critical decisions being made to recover species and manage scarce water resources.
H31H-02 INVITED
Overview of Endangered Suckers in the Klamath Basin: Does it Take One to Know One?
Severe water quality problems in the Klamath Basin of Oregon and California have led to critical fisheries concerns for the region. In the Upper Klamath Basin, two fish species, the Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) were listed as federally endangered in 1988. These species are large, long-lived, lake-dwelling fishes endemic to the Upper Klamath Basin. Declining population trends for both species were noted as early as the mid 1960's, however, the severity of these declines were not evident until the mid 1980's. At the time of listing, population structures were dominated by older individuals with little evidence of recent significant recruitment into adult populations. In the early 1990s there was evidence of recruitment for Lost River suckers. Successive years of large fish kills in Upper Klamath Lake from 1995 to 1997, however, substantially reduced adult populations of both Lost River and shortnose suckers. Additionally, the 1995 and 1996 fish kills appeared to have been selective for larger-sized individuals and would have disproportionately affected females and resulted in an overall lower reproductive potential. Water quality and physical habitat limitations are considered to be the most limiting factors to species recovery. Life history patterns of Lost River and shortnose suckers in Upper Klamath Lake have been severely disrupted by recurrent periods of poor water quality that appear to be the root cause of fish kills and likely negatively influence the production of juvenile suckers. Habitat degradation around Upper Klamath Lake and in its tributaries likely contributes to water quality problems and also limits the physical habitat needed for successful adult sucker spawning as well as larval and juvenile rearing. Ultimately, a better understanding of the factors that influence water quality in Upper Klamath Lake as well as developing a sound strategy for habitat restoration is needed to promote recovery of these species. Future challenges fisheries biologists in the Klamath Basin face include developing a better understanding of sucker population dynamics and habitat requirements at different life stages. One of the largest challenges, however, will be the integration of biological information on suckers with an improved understanding of water quality and physical habitat processes.
H31H-03 INVITED
The Role of Groundwater Hydrology in Water Resources Management in the Upper Klamath Basin, Oregon and California
Much of the water controversy in the upper Klamath Basin has centered on federal issues such as the competition for surface water between agricultural users and endangered fish; however, state and locally controlled water allocation issues are also becoming an increasingly important part of the discussion. Groundwater, which is managed by the state in Oregon, is currently being used to supplement climate-related surface water shortages that are occurring within tributary sub basins, and as a replacement for surface water, which in turn is being preserved for in-stream uses on the Klamath River. Increased groundwater development has raised questions among resource-management agencies and the public. Key questions regard the potential effects of groundwater pumping to water levels in wells, and the effects of pumping on groundwater discharge to springs and streams. Other questions concern the sustainability of increased groundwater use, and how best to use groundwater during various stages of drought cycles. This presentation will highlight the progress that has been made by the U.S. Geological Survey and the Oregon Water Resources Department in quantifying a generalized hydrogeologic framework, estimating recharge rates, determining hydraulic head distribution, characterizing groundwater/surface water interactions, and estimating groundwater use within the upper basin. An understanding of the dynamic behavior of the groundwater system, which dictates how stresses propagate spatially and temporally, has been developed by studying the long and short-term fluctuations of the water table and of spring discharge in response to known climatic and human-caused stresses. A particularly rich dataset of groundwater pumping and water level response information has been analyzed in the area of the most recent and intense groundwater development. Results to date indicate that it is likely that some ground water can be used to augment surface water during dry periods. However, considerable work remains in finding the optimal balance between the rates, distribution, and timing of pumping, and acceptable impacts.
H31H-04
Optimizing Numerical Modeling and Field Data Collection in an Interdisciplinary Study of Upper Klamath Lake, Oregon
Severe water quality conditions in Upper Klamath Lake (UKL), Oregon have led to critical fishery concerns for the region including the listing of Lost River and shortnose suckers as endangered species in 1988. Upper Klamath Lake was historically eutrophic but has become hypereutrophic, in large part due to land-Use practices in the Klamath Basin. In 2002, in cooperation with the US Bureau of Reclamation (BOR), the U. S. Geological Survey (USGS) began a three-year study of the behavioral response of radio-tagged Lost River and shortnose suckers to water quality conditions in the lake. To support the tracking study, an array of continuous water quality monitors was installed in the northern third of UKL, and wind speed and direction were recorded at two sites. Two Acoustic Doppler Current Profilers (ADCPs) were deployed in the lake for two summer months in 2003 and 2004, providing the first continuous measurements of water velocities. Hydrodynamics is the key factor determining the water quality in the lake, velocities measured at only two locations are not sufficient to even qualitatively describe the lake-wide circulation. To establish a quantitative description of the complex circulation in UKL, an unstructured grid 3-D hydrodynamic model (UnTRIM) was implemented. When the observed wind speed and direction were used to drive the model, the numerical model reproduced the wind 'set-Up' and 'set-down' at down wind and upwind ends of the lake, respectively. The UnTRIM model also reproduced the measured velocity time-series throughout the two-month ADCP deployment in 2003 with good agreement at a deep station. The correlations between the model results and ADCP data showed the same trend (slope nearly 1), but the R2 value was less than 0.5. This discrepancy is likely due to the fact that a uniform hourly averaged wind was applied over the lake. The complicated circulation patterns derived from the numerical model suggested a new strategy in designing the data collection network for the summer 2005 field season. Up to five wind anemometers have been installed around the lake to define the spatial variability of the wind field, and five ADCPs have been deployed in the lake to capture essential circulation features. The water quality monitoring network has been extended to cover the entire UKL, and monitoring stations have been placed at locations that will optimize the observation of important temporal and spatial variability in water quality as indicated by the circulation patterns predicted by the numerical model. The 2005 field data set will be used to refine the numerical hydrodynamic model upon which water quality modeling modules will be built. This case study demonstrated the use of field data to support numerical model implementation, and then the use of the numerical model results to improve the next cycle of field data collection. This loop optimizes the implementation of the numerical model and the effectiveness of field data collection.
H31H-05
Hydrogeology of the Groundwater Dominated Williamson River Subbasin, Upper Klamath Basin, Oregon
Pyroclastic flow and fall deposits from the climactic eruption of Mount Mazama that formed Crater Lake influence flow paths for ground water migrating into the Williamson River sub-basin from relatively small catchments within the Cascade Range. Snow melt runoff in May and June partitions between low discharge (<1m3/s) surface streams and ground water. Pyroclastic flows have an estimated infiltration rate of 10$^{-4}$ to 10$^{-6}$ m/s. Ground water moves primarily through underlying pumice and weakly lithified, medium to coarse grained volcaniclastic sedimentary rocks and intertercalated thin basalt lava flows of Pleistocene age. Since April 2000 ground water levels have declined throughout the basin and the slope on the potentiometric surface between Klamath Marsh and the Cascade Range has steadily declined. The result is earlier (7/21/2001 versus 6/17/2004) and longer periods (126 days in 2001, 248 days in 2004/2005) of no surface discharge from Klamath Marsh to the Williamson River. Ground water discharge within Klamath Marsh is estimated for late summer when precipitation is absent, Williamson River discharge into the marsh is low (0.5 m3/s), discharge from the marsh is absent, and evapotranspiration is maximum. Based on a surface area of 62 km2, the ground water discharge to Klamath Marsh is estimated at 3.1 to 3.7 x 105 m3/day. During the growing season evapotranspiration is 110 to 120% of ground water discharge resulting in water level declines of nearly 1 m below the elevation at which surface discharge from the marsh resumes on the Williamson River.
H31H-06
Sprague River geomorphology studies, Klamath Basin, Oregon
The Sprague River drains 4050 square kilometers with a mean annual discharge of 16.3 m3/s before emptying into the Williamson River and then upper Klamath Lake in southcentral Oregon. The alternating wide alluvial segments and narrow canyon reaches of this 135-km-long westward flowing river provide for a variety of valued ecologic conditions and human uses along the river corridor, notably fisheries (including two endangered species of suckers, and formerly salmon), timber harvest, agriculture, and livestock grazing. The complex history of land ownership and landuse, water control and diversion structures, and fishery alterations, provides several targets for attributing historic changes to channel and floodplain conditions. Recently, evolving societal values (as well as much outside money) are inspiring efforts by many entities to 'restore' the Sprague River watershed. In cooperation with the U.S. Fish and Wildlife Service, the Klamath Tribes, and many local landowners, we are launching an analysis of Sprague River channel and floodplain processes. The overall objective is to guide restoration activities by providing sound understanding of local geomorphic processes and conditions. To do this we are identifying key floodplain and channel processes, and investigating how they have been affected by historic floodplain activites and changes to the watershed. This is being accomplished by analysis of historic aerial photographs and maps, stratigraphic analysis of floodplain soils and geologic units, mapping of riparian vegetation conditions and changes, and quantitative analysis of high resolution LiDAR topography acquired for the entire river course in December 2004. Preliminary results indicate (1) much of the coarser (and more erodible) floodplain soils are largely composed of pumice deposited in the basin by the 7700 year BP eruption of Mount Mazama; and (2) the LiDAR digital elevation models provide a ready means of subdividing the river into segments with quantifiably different characteristics of channel width, sinuosity, slope, and incision (relative to adjacent floodplain elevations).
H31H-07
Use of Remotely-Sensed Snow Covered Area in Watershed Model Calibration for the Sprague River in the Upper Klamath Basin
This study presents a multiple-objective, step-wise, automated procedure for hydrologic model calibration in the Sprague River, a mountainous watershed in the Upper Klamath Basin. The procedure includes the sequential calibration of a distributed-hydrologic model's simulation of: (1) solar radiation, (2) potential evapotranspiration, (3) annual water balance; (4) snow-covered area; and (5) components of daily runoff. Measured snow-covered area data for model calibration was processed for the Sprague River basin from the MODIS/Terra Snow Cover 5-Min L2 Swath 500m. This data extends from February 24, 2000 to present. The surface hydrology of the Sprague River basin is dominated by snowmelt runoff, making snow-covered area prediction crucial for accurate streamflow forecasts. The multi-step calibration process ensures that intermediate model states and fluxes, as well as the annual water balance, components of the daily hydrograph, and snow-covered area are being simulated consistent with measured values. In comparison to models calibrated using streamflow data alone, this sequential calibration procedure produces model parameter sets more appropriate for hydrologic data assimilation.