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November 8, 2004

To Whom It May Concern:

In June and August, a bi-state group of agency and non-profit staff collaborated to create two longitudinal flow profiles of the Walla Walla River (mainstem). The purpose of these "Seepage Runs" was to create a spatial-profile of river flow at it naturally gains/ loses water as well as where and how much water is used. This was done for two periods during the 2004 irrigation season, June and August. The study reach began at the mouth of the Walla Walla River (with Colombia River) and extended up to the Bureau of Lands Management (BLM) trailhead on the South Fork Walla Walla River, the end of all irrigation diversions on the river. The North Fork of the Walla Walla River was also inventoried for flow for some specific WWBWC projects but was not modeled spatially. North Fork data was collected from the mouth until the OWRD gauge station.

The June "run" (June 22nd, 23rd and 24th, 2004) was conducted  specifically to analyze the early season flows during the period when the river transitions between the typically higher spring flows to that of the lower base-flows, summer months. This period is typically when irrigation water is starting to be utilized from the river and also correlates with the movement of cold- water fish species. This June 2004 was a particularly wet and unpredictable one, with the seepage run needing to be rescheduled twice due to prolonged rain-events that created unsafe measuring conditions.

The August seepage run (August 17th, 18th and 19th) was conducted to look at conditions during what are typically the lowest flows and most impacted water quality conditions on the river.

This project was conducted to support the following Walla Walla Basin activities:

(1) Assessment of water use/diversion during the irrigation season

(2) Assess flows for Chinook returns passage (CTUIR), directly useful for COE/CTUIR Feasibility Study Work (USACE’s: HEC-RAS modeling)

(3) Assess flows for HCP take analysis work (EES Contractors: Temperature Modeling: EES/Barber-WSU, Cramer Associates, PHABSIM modeling).

4) Assess flows, channel conditions, for modeling using TMDL temperature model (Heat Source) for WWBWC watershed-management project assessment (WWBWC/ODEQ/EPA)

(5) Assess flows/temperature for Bull Trout and telemetry work (for USFWS, UTAH State, CTUIR, ODFW, and WDFW)

(6) Information for WDFW's yearly habitat survey analysis and reports

(7) Calibration data for mainstem surface flow model (WWBWC)

(8) Provide water information for all other ongoing planning processes and research in the basin.

Methodology:

In general terms, a "seepage run" is a technique where measurements of all tributaries, distributaries and diversions are measured in order to create a longitudinal flow profile. Periodic instream measurements are also taken to account for channel bed gains and losses from ground water and return water from upstream irrigation diversions. The three general measured components of a seepage run are:

1. Mainstem Flow: The Walla Walla mainstem was measured periodically along the river as a test of flow conditions as it relates to accounting for inputs and outputs to the system. A combination of manual flow measurements and gauge station data was used to populate the flow profile.
2. Tributaries/Distributaries:  All known streams that provided water to or distribute from the Walla Walla mainstem inside the study reach were measured during the June seepage run. Many of the lower ephemeral tributaries (e.g. Vancycle Canyon) were not checked in August. Flow measurements were taken as close to a given tributaries confluence as was possible. Where confluence measurements were not available, the nearest upstream gauge or measurement site was used to quantify flow contributions.
3. Diversions:  This includes all pumps, weirs, and flumes that directly divert water from the mainstem river for consumptive use. Where measurement of these sites is not possible, an assessment of number and type of sprinklers is counted to estimate water use. Return or “tail” water was not explicitly accounted for during the seepage runs. Tail water, small springs and groundwater gains and losses are difficult to inventory, particularly on a project of this size. Their gross contributions can be accounted for implicitly in the instream flow measurements, but cannot be associated with a specific source.

Parameters and Protocols:

The following information was collected at flow sites. Generally, the outlined protocols were used by the collaboration partners: 

• Manual flow measurements: (units: cubic-feet-per-second (cfs) or gallons-per-minute (gpm), minimum of 25 x-sectional mmts, no more than 6% of total flow volume in any one cell, staff gauge reading (if at gauge site), x-sectional information (widths, depths, velocities), copy of q-notes for most sites is provided.
• Gauge data: where manual measurements were not available, a rated gauge station was used. As manual flow measurements were taken during the day, it was thought prudent to use an average-daytime-gauge-flow value to represent flow at any given station.
• Temperature manual (units: 0C or 0F). Manual temperature
• GPS lat/long coordinates.

Some sites also have:

• Conductivity (units: n.t.u., specific, adjusted for temp).
• Photograph of flow x-section/ diversion/ tributary mouth.

Longitudinal flow profile:

The data was processed and placed in an Excel 2000 spreadsheet format. In 2001 the Walla Walla River’s channel had been digitized in ArcView 3.3 (T-tools Extension) for the TMDL process by Oregon’s Department of Environmental Quality. In that same year, a Thermal Infrared Radiometer (TIR) was used in a flight along the river that captured infrared and photographs of the Walla Walla River mainstem. These images were used in conjunction with the digitized river broken into 25-meter segments to place each of the tributaries, diversions, and instream measurements in spatial relation to one another. This provides the data user the opportunity to assess spatial-rates of gains, losses, water use and relative quantities of instream flow.  

The attached disk includes to the following information:
[Contact bob.bower@wwbwc.org to request a disk of data.  There is a $7.50 fee to cover mailing costs for out-of-basin requests.]

1. Longitudinal Flow Profiles for June and August 2004 Seepage Runs.
   1. Graph of complete data set
   2. Table of complete data set
   3. Data set in longitudinal profile model
2. Raw data from each of the collaboration partners (in subfolders)
   1. Flow and temperature data: Q-notes
   2. Site photographs and water quality data (where available)
3. GIS layers (T-tools) for 25-meter segments (NAD 27 projection).
4. Copy of cover letter.

Data issues and concerns:

A project of this size with numerous groups collecting data in a large area is a difficult undertaking. The data was collected for this project and painstakingly placed using the aerial photograph-digital river segment described above. All site placements and data should be considered provisional as points of diversion (P.O.D.) can be moved or not used in a particular irrigation season.

Depending on the river conditions and measurement locations, it may be possible to use the seepage information for segment-by-segment estimates of channel bed gains and losses. However a close look should be taken at the timing and quality of each individual measurement to insure they are representative. Flow data should be used with the understanding that measurements of live-flow have error associated with them. Typically error ranges of 5-10% are used with live-flow measurement data.

As with any snapshot approach to analyzing a dynamic system, there are some major concerns to be aware of when using this data. Weather conditions can directly influence the irrigation flow profiles for each river. With June 2004 being wetter, it is most likely that diversions were lower than in an average June period. Also the time of data collection could also be an area of concern with this data set. All measurements were taken during the work week and it is known that a proportion of irrigators do irrigate exclusively at night or on the weekends. Therefore the water-use information may be representing a lower estimate of total use.

Outliers:

There are some locations along the river that are of particular interest due to apparent fluctuations in the expected versus measured flow. The lower Walla Walla River (Starting at USGS Touchet gauge) has higher than expected flows during the June seepage run. One possible explanation for this might be deduced by ground water contributions. A relief map of the area (USGS Quad) shows that as the Walla Walla River enters this segment, the valley begins to narrow significantly. This narrowing may act to force ground water (also moving downgradient in the unconfined alluvial aquifer) to move into the river causing higher flows. A second point of concern is the instream measurement provided at the WDOE Beet Road site during the June seepage run. Measurements made upstream and downstream of this site indicate that this value may be considerably off. Therefore this data was removed from the longitudinal profile, but left in the table notes for further consideration.

Project Partners:

1. WWBWC provided coordination, data processing and flow, temperature data for the entire project. Special thanks to Zeitel Gray, Hydrological Technical, for her exceptional patience and effort on this project.
2. USGS provided flow and temperature data for their Walla Walla Basin gauge stations. Thanks to Greg Rupert (USGS-Pasco) for his efforts.
3. WDFW provided flow and temperature data in WA portion of the study area. Thanks to Glen Mendel, Jeremy Trump, and the WDFW field crews for their efforts.
4. WDOE (Tri-state Steelheaders) provided data for each other gauge stations in the study area. Thanks to Brian Burns (TSS) and Jim Peterson (WDOE) for their efforts.
5. Also special thanks to WDOE watermaster: Bill Neve provided the diversion inventory for the entire Washington portion of the study area.
6. OWRD (WWBWC) provided diversion inventories and gauge station data for the entire Oregon portion of the study area. Thanks to Jim Chambers, Tony Justus, and Doug Nelson. Thanks also to Brian Wolcott (WWBWC) for his efforts in the diversion inventories.
7. Washington/Oregon Landowners provided river, stream and diversion access for this project. Thanks for your cooperation.
8. Washington and Oregon Irrigation Districts provided information regarding diversions for their systems. Special thanks to Brent Stevenson and Teresa Yeager (Walla Walla River Irrigation District), Jon Brough (Hudson Bay District Improvement Company) and Stuart Durfee (Gardena Farms Irrigation District #13).

For any questions, data corrections or concerns about this project, please contact us at the Walla Walla Basin Watershed Council.

Thank you for your interest and support.

Sincerely,

Robert J. Bower

Hydrologist

WWBWC

P.O. Box #68

Milton-Freewater, Oregon 97862

(541)-938-2170

bob.bower@wwbwc.org

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