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Corps Studies & Reports Issues Page

Preliminary Examination of Nooksack. Skagit and Snohomish Rivers, Washington

“The Skagit River is the largest and most important stream in the State. ... The principal difficulties to navigation are snags, drift piles, and shoals caused by them, also the tide fiats at the mouth.”

Capt. Harry Taylor Annual Report

In this report Capt. Taylor observes that the local Dike Districts are disorganized and have put the levees way too close to the edge of the river.  Also, he compares the height of the 1897 flood as compared to the 1896 flood.  His statements cast further dispersions on the accuracy of the 1923 Stewart Report.

3/2/1907 USACE Survey Map of the Skagit River in the Sterling Area

A wonderful piece of history showing depths of the river, height of the 1906 flood event, location of the Balls Riffle Ferry, pioneer farming family residences, location of the 1897 and 1907 channels, as well as surveys of land elevations.  Notice all depths are based on Low Low Water (i.e. different then sea level today).

2/29/1912 Corps of Engineers Preliminary Examination of Skagit River “In compliance with law, I have the honor to report, also, that it is not practicable to coordinate with any improvement of the river, either flood protection or the development and utilization of water power for commercial purposes so as to reduce the cost of improvement and render it advisable.”
1/26/1914 United States Engineer Office, Seattle, Wash. January 26, 1914 Survey of Skagit River, Wash. “Along both sides of the Skagit River below Mount Vernon dikes have been constructed to protect the adjacent lands from overflow, and as these dikes are generally close to the river banks, constant work is required to maintain them, all of which is now carried on by the diking districts. It is evident, therefore, that from the . standpoint of the United States there are certain practical objections to any change in the regimen of the river which may be considered as responsible for future difficulties with the dikes in this locality. In my opinion, no improvement of Skagit City bar should be undertaken by the United States unless local interests agree to cooperate to the extent of assuming all responsibility for the protection of the river banks above and below the works installed by the United States, so that no diversion of improvement funds can be urged by the diking districts for the protection of their dikes. Additional reasons for recommending such cooperation are the protection incidentally afforded the dikes at Skagit City bar by the proposed works, and the fact that the above estimate closely approximates the maximum expenditure which could be justified in the interests of navigation.”

Reexamination of the Skagit River

“The river is subject to sudden freshets at all seasons of the year.  It has been known to rise 18 feet in 24 hours and a rise of 10 feet in 24 hours is not unusual.  The maximum fluctuation is about 25 feet.  . . .  The dikes on both sides of the river are dangerously close to the edges of the banks, and the land back of them is highly improved and subject to overflow for miles in case of a break in the dike.”
1/31/1925 Preliminary Examination of Skagit River With A View To Control Of The Floods

This report relied heavily on the unpublished 1923 Stewart Report (See Stewart 1923 Report -- Retyped Version) and the people of Skagit County have been paying for it ever since.     ". . .the levees, to protect as much land as possible, were placed too close to the river on both sides, thus unduly restricting the channel.  A flood volume exceeding about 140,000 cfs below Sedro Woolley is likely to cause a breach in the levees.  A volume in excess of this, if retained in the floodway by higher levees, would endanger the bridge of the Great Northern Railway. . ."  . . .  "Floods of from 210,000 to 220,000 cfs may be expected about once every 25 years."  . . . "Diversion of the river would be possible at some point below Sedro Woolley, the diversion channel to run generally west into Padilla Bay."  . . .  Discharge and other data of value in connection with a study of plans for flood control are found in USGS WSP's and in an uncompleted report on Skagit River floods prepared by Mr. J.B. Stewart, of the USGS, jointly for that bureau and Skagit County, a copy of which has been furnished this office.  . . .  "No freight boats now go above Mount Vernon."  . . . "The Skagit River delta contains some of the richest farming land in the State."  100 year flood at Sedro-Woolley = 264,000 cfs.  500 year flood = 321,000 cfs. 

NOTE:  See also Notice and Minutes of Public Hearing In Connection With Preliminary Examination of "Skagit River, Washington, With A View To The Control Of Its Floods" Directed By Flood Control Act of May 31, 1924; Robert E.L. Knapp, Skagit County Engineer, Testimony for 11/26/1924 Hearing; H.L. Willis, Skagit River Improvement Committee Chairman Testimony for 11/26/1924 Hearing.


Preliminary Examination of the Skagit River

"Complete discharge data are not available.  . . .. The lower river is affected by the tide to the Great Northern Railway bridge, about 17 miles above its mouth. . . . In the early days what was known as the "Old Main River" was the principal channel.  . . . In accordance with an agreement between Skagit County and the United States Geological Survey, that department has made an extensive study of the flood flow in the Skagit Valley. The report has not yet been completed, but copies of portions of it have been furnished this office. . . . The channel is also restricted by the bridges above Mount Vernon and particularly at the Great Northern Railway bridge, whichis located immediately below a right-angled bend. The dike above this bridge was broken and the railway track to Burlington was washed out during the floods of 1909,1917, and 1921, the water flowing across country to Padilla Bay along the general direction of what was apparently a former river channel.
5/18/1928 MFR Re: Potential Dam Locations “Document identifies potential dam sites and gage locations on the Skagit and other rivers.  “The Dalles on the Skagit River.  A site for a low head dam, which would back the water up to the tailwater of Baker River plant.”
3/17/1932 Skagit River Flood Control River Enlargement and Dikes Proposal to provide for flood discharge of 220,000 cfs.  Water surface elevation 42 feet.  It was found to be impractical to confine the improvement to a system of dikes and channel enlargement.  Channel at BNSF RR Bridge would have to be widened 900 ft.  Near old highway 99 600 ft.    Again the Corps recognizes the Stewart Report as unpublished.
5/18/1932 Report on the Skagit River, Corps of Engineers, Seattle District One of the most detailed reports ever authored about the Skagit River.  Relied upon "An unpublished and incomplete report on Skagit river floods by Mr. J.E. Stewart, of the USGS, prepared in cooperation with Skagit County", to determine flood flows.
5/29/1937 Preliminary Examination of Skagit River & Tributaries The majority of this report uses the same verbiage as the 5/18/1932 Report including but not limited to population and rainfall figures.  "Local interests do not desire the construction of the by-peas at this time because of the large contribution required of them by the terms of the flood Control Act".  (pg 1)  . . .  It is pointed out in paragraphs 60 and 117, however, that during flood periods Skagit River overflows its bank downstream from Sedro Woolley and inundates a large portion of the delta, the flood waters returning to Puget Sound through many sloughs and small channels discharging into Skagit, Padilla and Samish Bays. (pg 10)  In 1923, Mr. J. E. Stewart, of the United States Geological Survey, collected data for, and partially completed, a report on Skagit River, jointly for his department and for Skagit County.  (pg 17)  . . .  Built without a comprehensive and coordinated plan, many of the dikes are poorly designed and improperly located. In an effort to enclose as much land as possible the dikes have been placed close to the river bank with little or no consideration given to alignment, river sections or other element entering into the proper design of such a system.  As a result frequent breakws, due to overtopping and to undermining of river banks and dikes, have occurred.  (pg 36)

Report on Survey For Flood Control of Skagit River and Tributaries

" . . .local interests are now unable to provide the required cooperation and that no modification of the physical features of the project will so reduce the cost to local interests as to make it possible for them to supply the required cooperation at this time."  (pg 1) 

". . .the February 1932 flood at The Dalles was measured as 147,000 second-feet, with a run-off during the 3 days of highest discharge of 602,000 acre-feet. It has been estimated that, if Shannon and Diablo reservoirs had not been in operation, the crest discharge at The Dalles would have been about 182,000 secondfeet, . . . (¶50 pg 18)  1940 LAND VALUES as determined in 1930 =". . .an average of $208 an acre." (¶56 pg 30)  The spring flood of 1894, which destroyed crops valued at $1,500,000, prompted the settlers to extend their system of dikes. The flood of 1897 washed out the roadbed of the Great Northern Railway between Burlington and Sedro-Woolley, flooded part of Mount Vernon, and caused a heavy loss of livestock and property above Concrete. The flood of 1906 caused a loss of $250,000.. The discharge at Sedro-Woolley during the 1897 flood was slightly greater than for the flood of 1906, so the damages resulting from the 1897 flood were probably on the order of $300,000. The flood of 1909 caused damages conservatively estimated at $1,500,000. It ruined many farms, destroyed several hundred head of livestock and washed out many miles of dikes and drainage ditches ,. The Great Northern Railway embankment between Burlington and Mount Vernon was washed away and serious damage done to the State highway, That part of Mount Vernon west of the river was entirely flooded.  (¶59 pgs 30-31)  River Improvement Fund -- "The work done by Mr. Stewart was also paid for from this fund."  On March 2, 1937 " . . . county officials stated that the county's financial position was such that it would be impossible at that time for the county to furnish the local cooperation required for the construction of the Avon By-pass as authorized under the existing project."  (¶77 pg 39)  It is estimated that a channel from Sedro-Woolley to Skagit Bay via the North Fork of Skagit River, adequate to carry safely a discharge of 220,000 second-feet, would require the excavation of approximately 56,000,000 cubic yards of material, and the acquisition of about 3,000 acres of agricultural land for right-of-way. (¶103 pg 47)  "...these same flood waters, under present conditions, reach Padilla Bay after flowing overland, . . ."  (¶110 pg 49)

12/1940 Flood Control Economic Justification Study Avon Bypass and Extension of Dikes to Sedro Woolley --Appraisal of Damages 1815 H.W. and 1921 H.W. -- Skagit River West of and Including Sedro-Woolley Samish River Delta -- Portions of Volume I General Appraisal Data and Maps December 1940 The document preparation began in 9/1940 and Volume 1 was completed 12/1940.  All 13 volumes were  7/1950.  "This appraisal of the Skagit River and Samish River Deltas is an estimate of damages that would result from a flood of equal magnitude and duration as the one of December, 1921, under present conditions. It is based on a peak discharge of 210,000 cu. ft. per sec. of the Skagit River near Sedro Woolley. "  . . . "GNRR 1921 H.W. mark on third pier north of steel truse" -- 37.4(pg 102)  1921 Flood Levels in Burlington 1921 H.W. 33.2 Spruce and Greenleaf  meaning water 2 feet deep -- 1921 HW 36.5 Holly & Fairhaven meaning water 2 feet deep -- 1921 H.W. 28.8  Garl (Burl Blvd) & Avon Water .2 in deep (pg 126)
6/15/1942 Appendix B to 1940 Report on Survey for Flood Control of Skagit River & Tributaries Appendix documents work performed by the Works Progress Administration (W.P.A.)  These projects consisted of brush revetment work in the Burlington Bend area, which began in November 1935.  "A considerable amount of damage to the various revetment units has been inflicted by log raft operations on the river in connection with logging activities being carried on in this area."
See also: 7/30/1940 Report on Survey For Flood Control of Skagit River and Tributaries
12/21/1949 Report on Skagit River Flood 27-28 November 1949 "Skagit River near Concrete rose from a flow of 30,000 cfs to a peak of 158,000 cfs in approximately 24 hours."  . . . Interruption of secondary highway travel on some of the lower valley roads begins when Skagit River flows reach about 67,000 cfs near MV." ... ". . .crest discharge of 158,000 cfs near Concrete is the maximum observed since 13 Dec 1921.. ."  $51,000 damage in Hamilton.  Levee breaks on Fir Island, Dodge Valley Road, Mill Town Levee broke.  Diablo and Shannon reservoirs had no effect on the flood because they were full at the time.  Ross had plenty of storage and held everything for five days.  Reduction at MV was estimated at 25,000 cfs. which reached a peak of 112,000 cfs.
2/28/1951 Skagit River – Rough Estimate of Flood Damages from Sedro-Woolley to Mouth of Skagit River This is a wonderful historical document drafted for the purpose of computing the 1951 flood damages however it also contains detailed information on the floods of 1949, 1932, and 1921.  What it clearly shows us is the reliance on the James E. Stewart data 10 years before it was published.
2/21/1952 Report on Survey for Flood Control of Skagit River and Tributaries “The existing reservoirs are not effective in preventing major flooding in the Skagit Valley, Diablo Reservoir is ordinarily maintained at a high level by Ross storage and has no flood storage, Shannon Lake is likewise held at a high level if stream flow permits, but an incidental degree of minor flood protection might be available if the reservoir should be drawn down because of deficient run-off before a flood, Ross Reservoir above Diablo has a large amount of storage, primarily for power, but the Federal Power Commission has required a reservation of winter flood control storage space. Studies are under way to determine the amount of such storage, and it is believed that it will not exceed 200,000 acre-feet. Because of its far upstream location Ross Reservoir storage cannot greatly reduce major floods on the lower Skagit River, The effectiveness of Ross storage in reducing peak discharges depends upon location of the storm center and other variable storm characteristics, Estimates based on average conditions indicate that crest reductions varying between 15,000 and 25,000 second-feet may be expected at Sedro Woolley.”
2/21/1952 Excerpts from Report on Survey for Flood Control of Skagit River and Tributaries Paragraphs suggest a design of 250,000 CFS at Mount Vernon.  Skagit County failed to reconcile those statements here with their record of 11 floods from 1896 to 1960 with a flood volume of 100,000 CFS to 195,000 CFS, proving the hydrology of the Skagit River was in question as early as fifty years ago.

See: Ltr to Colonel R.P. Young, US COE, Seattle District, Re: Legislative Council Meeting
2/21/1952 Appendix to Report on Survey for Flood Control of SKAGIT RIVER AND TRIBUTARIES, WASHINGTON Excellent description of the Standard Project Flood and current (as in 1952) potential dam sites.
5/11/1952 Skagit River Report, Re: Future Skagit River Dams & Flood Storage Calculations on the amount of acre-feet necessary to eliminate Skagit River Flood Risk.
2/3/1961 USACE Seattle District  Plan of Survey Skagit River Flood Control Study  With regulation at Ross and Upper Baker Dams, a 150,000 cfs flow at SW has a frequency of about 25 years. ... Flows of 210,000 cfs at SW have frequencies of about 200 years under existing conditions.  (NOTE:  REMEMBER THIS IS BEFORE ADDITIONAL STORAGE BEHIND UPPER BAKER.) ... damages from flows of this magnitude would total about $6,600,000.  ...  objective of this study is to find the most economically feasible solutions.
See also: Public Hearing on Flood Control for the Skagit River Basin, 8 February 1961
2/8/1961 Summary of Public Hearing on Flood Control The Bypass project was favored by the Dept of Game and Fisheries because it would have no effect on the existing Skagit River fishery resources.”
2/8/1961 Public Hearing on Flood Control for the Skagit River Basin, 8 February 1961

I am particularly interested in securing information on the nature and scope of the flood control improvements desired; the problems and difficulties encountered under the present conditions, and the proposed developments which would utilize the desired improvements that you would suggest.” (Col. Young, US Army Corps of Engineers)

2/8/1961 Missing Exhibits to Public Hearing Transcript This is a series of letters that were submitted during the 2/8/61 Public Hearing.  Dike 12:   "The dike has been raised an overall height of 2 feet for a distance of approx. 9 miles.  As they continue to build restrictions into the river below us, narrowing the stream flow, it will be necessary to raise the height of the dike." La Conner:  "In 1882, six feet of flood water inundated the land, damaged crops, and broke the dikes.  In 1886 the Skagit River overflowed and froze and in 1887 a late spring freshet damaged crops."  Dike 17:  District formed in 1907.  Letter identifies where the levee broke in 1917 & 1921.  Raised their levee 18 inches above the 1951 level.  Dike 20: (Nookachamps) Dike not high enough to keep out water over 24 feet.  Dwelly:  Supported dredging for commerce but very opposed to Faber Dam.  WSDOF:  Skagit "most valuable" tributary to Puget Sound in sustaining commercial sport fishing.  65% of the Chinook salmon spawning area is located on main stem of the Skagit and tributaries above proposed Faber dam site.  Supported building of Avon Bypass.  Dairy Farmers: "They know what has happened to them in past floods..."  Many dairy cows died in the 1951 flood.  Mt. Vernon:  Estimated over 4 million dollars of property in harm's way.  Figure included 600 homes and 1,400,000 sq. ft. of commercial property and 10 miles of sewer lines in flood area.    Total damages est. $6,200,000.  Burlington:  No loss since 1950.  Made no specific recommendation for a flood control project.  Needed to educate voters on flooding issue.
See also: Public Hearing on Flood Control for the Skagit River Basin, 8 February 1961
7/13/1962 Estimate of Public Values Skagit River Flood Plain “50-Year Trend. - Assuming the completion of a flood control project, the cities will expand rapidly into the flood plain with residential sections and outlying shopping centers.  Projecting a very slow, steady growth for the Puget Sound Region, the flats around Mt. Vernon and Burlington will be in great demand as all available coastal uplands will be utilized for residential use near dispersed industrial sites along the coast.”
1/18/1963 Feasibility Report, Skagit River, Washington (Navigation)

NOTE TO REVIEWER:  This is a very poor copy of the original and very difficult to read.  It helps to enlarge it to 125-150%.  This document looked at the history of a navigation project between Mt. Vernon and Concrete originally authorized by Congress on May 13, 1947.  The final results are in this report as well as a lot of statistical history on logging and local businesses.

"Tug operators advised that a 100-ft channel width and a 6 foot depth would be sufficient for foreseeable navigation requirements." (13) ... Approx 1,520,000 CY of material would be dredged. (15 & 21)  Estimated that annual maintenance dredging would consist of 380,000 CY.  (22b)  Two mills at SW sell annually, an average of 10,500,000 board-feet of lumber to the US Army. (27)  Total annual benefits of barge canal would be $592,000. (28)  Annual cost $474,000. (29) Amt needed to complete study $45,000. (30) The Skagit River navigation study has been authorized and intermittently underway since 1947 In view of this fact ... an effort should be made to complete the study as soon as practicable.  ... $15,000 needed to complete the study be allocated early in fiscal year 1964. (31)

See also Dredging Issue page for related documents and 4/12/1949 Minutes on Public Hearing on Skagit River, Washington, Relating to Navigation
8/1/1963 Lower Sauk River Dam Analysis & Pertinent Data Analysis of power requirements for potential dam on the Sauk River encompassing 712,000 acre-feet of which 200,000 acre-feet was to be used for flood control storage.

USACOE Avon Bypass Reactivation Report

Unregulated 100yr fld 250,000 to 300,000 cfs (pg 2); The 35-year level of flood protection provided by the Avon Bypass with levee and channel improvements would protect against 79 percent of average annual flood damages under present conditions.  These flood damages are 75 percent agricultural and only 25 percent urban.  Therefore, the project is now required essentially for the protection of agricultural lands, and the 35-year level of protection is well suited to present development.  . . .  The semi-pervious foundation conditions preclude any general raising of levees without extensive broadening of the levee sections, construction of cutoffs to reduce seepage, and relocation of the road systems adjacent to the levee system. (pg 4)  To achieve the same results as the Bypass and levee improvements, the channel would have to be widened from 300 to 600 feet from the downstream limits of Sedro Woolley to the mouth of the river, a distance of over 20 miles.  (pg 6)  ... At Mt. Vernon the 1932 flood of 140,000 c.f.s. has a 12-year frequency; the 1921 flood of 182,000 c.f.s. has a 30-year frequency; and a flood of 245,000 c.f.s, would have a 100-year frequency.  ... 278,000 at SW (Table 2)
11/22/1963 Corps Avon Bypass Plan Informational Bulletin Plan would create a 8 mile long cold clear lake. U.S. Fish and Wildlife developed resident trout fisheries in Bypass. Minimum flow of 100 cfs required. Lower section of Bypass would be used for migratory fish rearing.
3/1965 COE Skagit River Flood Control Report

100 yr flood at Sedro Woolley 239,000 cfs. . . . The existing levee system rests on a foundation of silts and sands common to the delta area. Differential heads of water in flood flow periods result in seepage through levee embankment and levee foundations, causing boils and blowouts that flood adjacent croplands.  . . .  The semi-pervious foundation conditions preclude any general raising of levees without extensive broadening of the levee sections, construction of cutoffs to reduce seepage and relocation of the road systems adjacent to the levee system. . . . Widening the Skagit River to carry flood flows is also infeasible. To achieve the same results as the Bypass and levee and channel improvements would produce, the channel would have to be widened from 300 to 600 feet from the downstream limits of Sedro Woolley to the mouth of the river, a distance of over 20 miles.  . . . The possibility of substantially increasing existing levee heights was opposed by the City Engineer of Mount Vernon and representatives of diking districts because of the hazard of underseepage and blowouts through porous foundation materials.  . . .  Representatives of the Washington State Department of Game and the U. S. Fish and Wildlife Service stated that the proposed levee and channel improvements would not adversely affect the runs of anadromous fish in the Skagit River, . . . The Avon Bypass project for flood control was endorsed by the Washington State Departments of Conservation, and Commerce and Economic Development, the Skagit County Board of Commissioners, the Skagit County Flood Control Council, the City Engineer of Mount Vernon, and local residents. The Chairman of the Skagit County Board of Commissioners stated that the people and taxpayers of Skagit County could be assured that they would have the right to vote on funding of local cooperation requirements for the project.  . . .  Opposition to the Bypass project was expressed by representatives of Fire District No. 6 and Diking District No. 12 on the grounds that the Bypass cost would be excessive and would sever both districts and make access difficult.  A petition signed by 740 persons was presented by a citizens' group that opposed the Bypass and any plans to modify the Bypass for other purposes.

7/9/1965 Series of MFRs & Letters Mostly Addressing 8 Possible Dam Sites and Impacts of Wild and Scenic River Act 7/9/65 8 sites were Cascade River, Lower Suiattle River; Upper Suiattle River; Upper Sauk River; Lower Sauk River; Cooper Creek; Thunder Creek; and Faber site (on Skagit about 6 miles upstream from Baker River).  7/1/65  "A decision to commit a portion o the river basin to a Wild (and Scenic) River category appears premature at this time.  6/18/65 "One hundred year flood protection is vitally necessary for continued progress in Skagit county. 6/29/65 The purpose of this meeting was to inform Seattle Light representatives of our proposed upstream storage studies in the Skagit River basin, determine sites at which City Light has made studies, and obtain data on power studies made by the city. 4/7/65  Ltr fm private engineering company to Corps re Cape Horn.
See also: 8/12/1965 DF re Skagit River Upstream Storage Geologic Reconnaissance
7/15/1965 Ltr from Corps to Skagit County Board of Commissioners re Flood Control & Other Improvements Report "I am pleased to enclose two copies of this report for your use."  . . ."I believe completion of the report is an important first step in the development of a comprehensive flood control plan for the Skagit River basin. The improvements recommended, in combination with the authorized Avon Bypass, would provide more than 35-year protection for nearly all of the flood plain downstream from Sedro Woolley, Washington. As part of our continuing comprehensive studies for the Skagit River basin, we hope to develop a plan that will ultimately provide 100-year flood protection for the basin flood plain."

DF re Skagit River Upstream Storage Geologic Reconnaissance

"This report covers certain geologic phases of upstream storage -sites as viewed on a 5-day reconnaissance by Messrs. A. S. Cary, F&M Branch and W. R. McKinley, Project Planning Branch, into the Skagit drainage area."  . . . The Skagit Valley far upstream has a depth of fill near 500 feet and if the rock floors of the Sauk and Skagit are concordant, the depth is well below sea level."
See also: 7/9/1965 Series of MFRs & Letters Mostly Addressing 8 Possible Dam Sites and Impacts of Wild and Scenic River Act
9/7/1965 Corps letter to Congressman Meeds re Avon Bypass Extensive letter justifying the Bypass concept.  Addresses why dredging won't work and setback levees too expensive.
3/1/1966 Supplement to Review Report on Flood Control and Other Improvements on Skagit River, Wa., Corps of Engineers, Seattle District Report address a myriad of flood control options including dredging, widening channel, dredging the mouth of the river and levee raising.  
3/1975 Public Brochure re Additional Flood Control at Upper Baker Project

Dept. Ecol. = State Department of Ecology
EPA = Environmental Protection Agency
PNWWA = Pacific Northwest Waterways Association
SWCD = Soil & Water Conservation District
Sierra = Sierra Club

A comprehensive plan, completed in 1971, called for increasing Skagit River flood control through use of reservoir capacity provided by Puget Sound Power and Light Company's Upper Baker hydroelectric power project in addition to the 16,000 acre-feet of storage space now available during the winter flood season. The detailed feasibility investigation being completed by the Corps of Engineers was in follow-up to the comprehensive study and undertaken under the same authority.  . . .  Land use zoning, development restrictions, flood proofing and early flood warning are flood plain management elements of this alternative which would be continued by Skagit County and the State of Washington.  . . . Baker Lake would be lowered to provide a total of 74,000 acre-feet of flood control storage between 15 November and 1 March each year.  . . .  Although increased flood control capability has the potential of creating increased development pressure on flood plain lands, especially those close to urban areas and those now protected by dikes and levees, this pressure is expected to be minimal.  . . . However, the application of stringent flood plain management techniques and flood plain zoning by Skagit County, as called for in the recommended plan, should reduce the likelihood and severity of such losses.  . . . The U.S. Fish and Wildlife Service and the National Marine Fisheries Service late in the study asked that flood control drawdown occur earlier than necessary for flood control in order to benefit Baker Lake salmon production.  This earlier drawdown would increase power losses and, therefore, would have to be justified by fishery enhancement benefits. No current provision exists in the FPC license for such a project operation change.  Because of this and the lack of data on fish production, the Corps study did not evaluate the early drawdown proposal.  . . .  Detailed engineering, economic and environmental impact studies were conducted over the past 2 years . . . Land use. The increased flood protection provided by this alternative (additional 58,000 ac ft storage) would not be sufficient to allow relaxation of current restrictions on intensive developments in flood hazard areas. Therefore, no effect on land use is expected.


False sense of security. Encourages development of flood plain for uses incompatible with flooding.  (Sierra) Would create a false sense of security which could induce continued building in floodprone areas. (R. Hammond, SWCD)  . . .  Not enough protection. Only corrects about 8 percent of the total flood damage of the basin. (Dept. Ecol.) Watershed above Upper Baker includes less than 7 percent of area of the Skagit at Mt. Vernon and about 10 percent of runoff volume. This degree of control would be small under severe conditions.  (SWCD)  . . .  Storage will increase. The additional flood storage could make the difference between the (a) disaster or high river stage. (PNWWA) Additional flood storage at Upper Baker will not adversely affect the environmental values of Skagit Valley. (EPA) It is only a start on the overall control program for Skagit, and its benefits will more than justify the costs.  (SWCD)

4/22/1976 Corps DF re Environmental Assessment of Levee Repairs After 1975 Flood Event Repairs took place on Cockreham Island.  Skagit floods "characterized by sharp rises of relatively short duration from October through March."  . . .  "The Skagit River system produces more runoff than any other river basin in the Puget Sound area."  100 year flood 266,000 cfs.  50-year flood 224,000 cfs.  Zero damage 60,000 cfs.  Present levee system with 2ft of freeboard 84,000 to 130,000 cfs or 3 to 11 year protection.  . . . Ross Dam controls about 30 percent of the basin's runoff with 120,000 acre-ft of storage space. . . . During the 1972-1973 collection period,  nearly 14,400 salmon were captured,  trucked, and  released into Baker Lake and adjoining artificial spawning beaches . They consisted  of 10,000 sockeye , 4, 000  coho, 250  chinook , and 30  chum.  In  addition, 50 steelhead trout were captured and released.  . . . The damaged areas at the   town  of Hamilton, and the  four damaged portions between Hamilton and Lyman occurred  where the  high water flow  was  either restricted or at a sharp  change in direction without adequate floodway area to handle the  resulting turbulence.  The floodwater was most destructive where the levee was breached; in some of these cases the water velocity cut a channel from the river through the vegetated bench and beyond into the agricultural area. . . . The greatest loss to fish will be the loss of eggs placed in the gravels by spawning fish prior to the flood.
7/1966 Flood Plain Information Study, Skagit River, Summary Report Draft 17 page summary report of the Technical Report performed by Corps on behalf of Washington State Department of Conservation (forerunner of Dept of Ecology).
6/1977 U. S. Army Corps of Engineers Report on Floods of December 1975 and January 1976 Partial report containing sections pertinent to the Skagit River.  Storm began on 29th of November and lasted to the 4th of December.  "Baker River Basin amounts to 11 percent of the Skagit river drainage." . . ."Outflow from Lake Shannon continued to increase. . .24,800 c.f.s..". . . "Without flood control regulation by Ross Dam and the Baker River Projects, the flood peak would have been about 39.9 feet (147,000 c.f.s.), 3 feet higher than the observed peak."  Third highest peak since 1940.  One of the more interesting things about this report is the areas they had to sandbag to keep the levees from failing.
12/1978 USACE Levee Improvement Study Studygram December 1978 Analysis of proposals to improve levees from the 3-Bridge Corridor to the delta for the 1979 Levee Improvement proposals that failed at the polls.  One alternative, 3D, would provide, 29,700 acres of land with rural protection (50-year), and 22,000 acres of land would be provided urban protection (100-year). The project would prevent 100-year Skagit floods from overflow to the Samish. However, flooding would still occur due to Samish River flows on 14,500 acres. The Nookachamps-Clear Lake area would experience an increase in the 100-year water surface elevation of about 4.5 feet. 
See also: 1979 Levee Improvement Project Historical Index
8/21/1997 Skagit Fisheries Investigation Feasibility Study It has been inferred that the massive loss of slough habitat in the lower Skagit River has reduced overwintering productivity of the river and placed increasing pressure on the few remaining sloughs.  A survey should be completed to quantify the amount of slough habitat currently open to fish passage along the project area and to quantify any further loss of slough habitat due to the proposed project.  If  losses occur beyond the current condition, engineering solutions to retain adequate fish passage should be devised.
6/6/2003 June 6, 2003 Skagit River Feasibility Study Executive Committee Status Report “The existing condition hydraulic models (UNET and FLO-2D) have undergone independent technical review (West Consultants, Inc). Levees throughout the system were recently field inspected and reanalyzed based on new survey data, resulting in significant changes in probable levee failure and non-failure elevations. This revised information has been inputted to the hydraulic models. Accordingly, new inundation maps for the 10-, 25-, 50-, 75-, 100-, 250-, and 500-year events are now being formatted and are scheduled to be completed this week.”
3/2011 Skagit River Basin Skagit River Flood Risk Management Study Draft Report Hydraulic Technical Documentation “This report documents the work conducted for the Skagit River Flood Risk Management Feasibility Study to develop hydraulic computer models and to establish existing without project hydraulic conditions.  . . .  The emphasis in this report is on hydraulic modeling for the lower Skagit River downstream from Sedro-Woolley. The damage reaches that are evaluated start at Sedro-Woolley and extend down to the mouth at Skagit Bay.  . . .  Revisions to the hydraulic models used for the Flood Risk Management Study and preparation of the present 2011 update to the Hydraulic Technical Documentation were carried out by Northwest Hydraulic Consultants Inc. (NHC) under contract to the local sponsor, Skagit County (contract C20080424, Task Assignment 4, authorized 15 October 2009).” 

Report also discusses impacts of bridge debris, potential levee breaches and hydraulic model calibration & validation.  Page 37 of this report (page 41 of the PDF) is devoted to debris loads at the BNSF RR Bridge.
4/15/2011 Flooding in Western Washington: The Connection to Atmospheric Rivers “This study utilizes multiple decades of daily streamflow data gathered in four major watersheds in western Washington to determine the meteorological conditions most likely to cause flooding in those watersheds. ...  The flooding on the four watersheds occurred during the landfall of ARs [Atmospheric Rivers] within the warm sectors of extratropical cyclones that were accompanied by warm advection, lower-tropospheric temperatures 4-6°C above normal, strong low-level water vapor fluxes from over the Pacific, and low-level moist-neutral stability. The enhanced onshore vapor fluxes and weak static stability provided a favorable environment for orographic precipitation enhancement across the region’s steep terrain. More generally, all peak daily flows that exceeded a 5-year return period on non-consecutive days in each of the four basins of interest between WY1980-2009 were associated with landfalling ARs.”

One of those basins of interest was the Sauk River.
2/2012 Revised Skagit River General Investigation Study Scoping Summary Report for the Draft Feasibility Study and Environmental Impact Statement

“The U.S. Army Corps of Engineers, Seattle District (USACE), in cooperation with Skagit County, is preparing a Draft Environmental Impact Statement (DEIS) under the National Environmental Policy Act (NEPA) for a proposed flood-risk management General Investigation (GI) Study for the Skagit River Basin from Ross Lake to the river mouth at Skagit Bay. This study was requested by Skagit County because of the potential for significant flooding on the Skagit River.
“An initial notice of intent (NOI) for this project was originally published in the Federal Register on November 20, 1997, for a Skagit River Flood Damage Reduction Study (62 FR 62019). Since the original NOI was issued in 1997, the study has evolved to meet new challenges and include ecosystem considerations associated with Puget Sound Chinook salmon and bull trout species listed as threatened under the Endangered Species Act (ESA). On July 29, 2011, an additional NOI was published, recommencing the scoping process (76 FR 45543) (see Appendix A). The purpose of this most recent NOI was to provide opportunity for additional public input and ensure that the study still accurately reflects stakeholder resource issues and concerns.”

UPDATED “This final Scoping Summary Report for the Skagit River General Investigation Study has been revised to include a comment letter from the U.S. Environmental Protection Agency (EPA) that was inadvertently excluded from the October 2011 Scoping Summary Report. Revised text is italicized. ... Address environmental justice in the EIS. ... Consider a natural processes alternative as one of the alternatives in your range of reasonable alternatives.  Develop and disclose project specific standards of significance.

See also: 11/26/2011 Comments on October 2011 Corps Scoping Summary Report