HENRY HAGG LAKE 2001 SURVEY FOR FTH U.S. Department of the Interior Bureau of Reclamation Form Approved REPORT DOCUMENTATiON PAGE 0MB No. 0704-0188 I. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED December 2001 Final ______________________________________ 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Henry Hagg Lake PR 2001 Survey 6. AUTHOR(S) Ronald L. Ferrari _____________________________ 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Bureau of Reclamation, Technical Service Center, Denver CO 80225-0007 _____________________________ 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY REPORT NUMBER Bureau of Reclamation, Denver Federal Center, P0 Box 25007, DIBR Denver CO 80225-0007 II. SUPPLEMENTARY NOTES Hard copy available at Bureau of Reclamation Technical Service Center, Denver, Colorado 1 2a. DISTRIBUTION/AVAILABILITY STATEMENT 1 2b. DISTRIBUTION CODE 13. ABSTRACT (Ma,irnurn 200 words) The Bureau of Reclamation (Reclamation) surveyed Henry Hagg Lake m May 2001 to develop a topographic map and compute a present storage-elevation relationship (area-capacity tables). The underwater survey was conducted near lake elevation 279.1 feet (NGVD29). The underwater survey used sonic depth recording equipment mterfaced with a global positioning system (GPS) that gave continuous sounding positions throughout the underwater portions of the reservoir covered by the survey vessel. The above- water topography was determined by aerial data collected on November 28, 1999 near lake elevation 268.5. The new topographic map of Henry Hagg Lake was developed from the combined 1999 aerial and 2001 underwater measured topography. As of May 2001, at maximum water surface elevation (feet) 305.8, the surface area was l,l4lacres with a total capacity of 64,812 acre-feet. The 2001 underwater survey measured greater surface areas than the original survey from reservoir elevation 255.0 and below. This resulted in the 2001 study computing a greater total reservoir capacity than the original computations. The 2001 analysis concluded these differences were due to under reporting of the original surface areas below elevation 260.0. The 2001 study measured an active capacity loss (elevation 235.3 to 305.8) of 352 acre-feet that could be attnbuted to sediment accumulation. Due to under reporting of the original surface areas, the 2001 study reported an increase of inactive storage (below elevation 235.3) of 2,580 acre-feet, resulting in a total net capacity increase of 2,228 acre-feet. 14. SUBJECT TERMS 15. NUMBER OF PAGES reservoir area and capacity/ sedimentation! reservoir surveys/ sonar/ sediment distribution! _______________________ contour area! reservoir area! sedimentation survey! global positioning system 16, PRICE CODE 17. SECURITY 18. SECURITY 19. SECURITY CLASSIFICATION 20. LIMITATION OF CLASSIFICATION CLASSIFICATION OF ABSTRACT ABSTRACT OF REPORT OF THIS PAGE UL UL UL ' UL NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std, 239-18 298-102 Henry Hagg Lake 2001 Survey by Ronald L. Ferrari Sedimentation and River Hydraulics Group Water Resources Services Technical Service Center Denver, Colorado December 2001 ACKNOWLEDGMENTS The Bureau of Reclamation's (Reclamation) Sedimentation and River Hydraulics Group of the Technical Service Center (TSC) prepared and published this report. The hydrographic survey was conducted by staff of the Reclamation's Ephrata Field Office under the guidance of Cory Stolsig. The underwater data editing was conducted by Cory Stolsig. Ron Ferrari of the TSC completed the data processing needed to generate the new topographic map and area-capacity tables. Sharon Nuanes of the TSC completed the final map development. Kent Collins of the TSC performed the technical peer review of this documentation. Mission Statements The mission of the Department of the Interior is to protect and provide access to our Nation's natural and cultural heritage and honor our trust responsibilities to tribes. The mission of the Bureau of Reclamation is to manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American public. The information contained in this report regarding commercial products or firms may not be used for advertising or promotional purposes and is not to be construed as an endorsement of any product or firm by Reclamation. The information contained in this report was developed for the Bureau of Reclamation; no warranty as to the accuracy, usefulness, or completeness is expressed or implied. 11 CONTENTS Page Introduction I Summary and Conclusions 1 Reservoir Operations .......................................................... 2 Reservoir Area and Capacity .................................................... 3 Topography Development .................................................. 3 Development of 2001 Contour Areas ......................................... 4 2001 Storage Capacity .................................................... 4 Study Conclusions ........................................................... 5 References .................................................................. 6 TABLES Table 1 Reservoir sediment data summary (page 1 of 2) ................................. 7 1 Reservoir sediment data summary (page 2 of 2) ................................ 8 2 Summary of 2001 survey results .............................................. 9 FIGURES Figure 1 Henry Hagg Lake location map ............................................. 10 2 Scoggins Dam, plan and sections ............................................ 11 3 Henry Hagg Lake topographic map, No. 417-D-803 ............................ 13 4 Henry Hagg Lake topographic map, No. 417-D-804 ............................ 15 5 2001 area and capacity curves ............................................... 17 Hi INTRODUCTION Henry Hagg Lake, formed by Scoggins Dam, is located in Washington County on Scoggins Creek which is approximately 5 miles southwest of the city of Forest Grove and 25 miles west of Portland, Oregon (fig. 1). Scoggins Dam and Henry Hagg Lake are principal features of the Tualatin Project with the purpose of providing irrigation, recreation, flood and water quality control. The dam is owned by Reclamation who contracted with the Tualatin Valley Irrigation District for the operation and maintenance of the project facilities. The drainage area above Scoggins Dam is 40.6 square miles and allis considered sediment contributing. Scoggins Dam was completed in 1975 with first storage in January of 1975. The dam is a rolled, zoned, earthfill structure whose dimensions are (fig. 2): Hydraulic height' 111 feet Structural height 151 feet Top width 30 feet Crest length 2,700 feet Crest elevation 313.0 feet2 The spillway is located on the left abutment and includes an inlet channel, gate structure of two 19- by 20.5 foot radial gates, a chute, and a stilling basin. The gates allow controlled spillway releases into a combined spillway and outlet works discharge channel. The spillway provides a maximum discharge of 14,100 cubic feet per second (cfs) at maximum reservoir elevation 305.8. The outlet work is located at the left abutment and consists of an inlet channel, trashrack, upstream and downstream tunnels, and high-pressure gates to control the releases. The outlet works were designed to release a total of 355 cfs at reservoir elevation 260.3. SUMMARY AND CONCLUSIONS This Reclamation report presents the 2001 results of the survey of Henry Hagg Lake. The primary objectives of the survey were to gather data needed to: • develop reservoir topography • compute area-capacity relationships A static global positioning system (GPS) control survey was conducted to establish horizontal and vertical control points around the reservoir for the aerial survey that was conducted in November of 1999. The horizontal control was established in Oregon north state plane coordinates in the North American Datum of 1983 (NAD83). The vertical control for the established points was in the North 'The definition of such terms as "hydraulic height," "structural height," etc. may be found in manuals such as Reclamation's Des:gn of Smill Dams and Guide for Preparation of Standing Operating Procedures for Dams and Reservcizrs, or ASCE's Nomenclsture for Hydraulics. 2Elevation levels are shown in feet. All elevations shown in this report are based on the original project datum established by U.S. Bureau of Reclamation which are tied to the National Geodetic Vertical Datum of 1929. It is 3.49 feet lower than North American Vertical Datum of 1988. 1 American Vertical Datum of 1988 (NAVD88). This study determined that for the established control points the average elevations in NAVD88 were around 3.49 feet higher than the Reclamation project construction datum that was tied to the National Geodetic Vertical Datum of 1929 (NGVD29). All elevations in this report are referenced to NGVD29. The aerial survey was flown in fall of 1999 around reservoir water surface elevation 268.5 and the underwater survey was conducted in May of 2001 around reservoir water surface elevation 279.1. The bathymetric survey was run using sonic depth recording equipment interfaced with a differential global positioning system (DGPS) capable of determining sounding locations within the reservoir. The system continuously recorded depth and horizontal coordinates of the survey boat as it was navigated along grid lines