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Ross Dam Issues
3/7/2010 Retyped for clarity and emphasis 8/14/1953 Corps document.

See Seattle District Office Ltr re: Flood Control Requirement and Operating Procedure for Ross Reservoir, Skagit River, Wash. for original document.		 For this document we took the original 8/14/1953 document, retyped it verbatim and added emphasis, footnotes, and a flood CFS table to show what the Corps was studying.  The document shows us that among many other things, the Corps used the Sedro-Woolley Stewart figures to compute the Ross Dam storage requirements, this despite the fact the Stewart data wasn’t published yet, and presents a serious question as to why they discarded the Stewart Concrete figures before 1924; if the 1909 flood happened today it would carry approximately only 185,000 CFS not the 220,000 CFS Stewart estimated; and the Corp recommended storage only “start” to be accomplished on November 1st even though 24% of the flood events “studied” happened in October.  This document is a must read for everyone interested in storage issues for the Skagit River.
7/15/1946 Congressman Henry "Scoop" Jackson Letter to Corps of Engineers, Re: Application to Increase Ross Dam Height and Request for Flood Control “As you will note, the Skagit County Planning Commission and the Board of County Commissioners have requested that any grant of right to increase the height of the Ross Dan be granted only upon the condition that the upper 15 feet of the dam, as either completed or partially completed be reserved as storage for flood waters and for flood control purposes.”

Note: Upper 15 feet of full pool translates into 170,741 acre-feet of storage.  As of 2/2010, Ross Lake has 119,629 acre-feet of flood control storage.
9/26/1946 Seattle District Corps of Engineers Letter, re: Ross Dam Flood Capacity Needs “From the tabulation in paragraph 4, it can be seen that 100,000 to 200,000 acre-feet of storage would control the winter floods of record on the upper Skagit.”
11/20/1946 Acting Chief of Engineers for the Army Corps of Engineers Letter to Federal Power Commission, Re: Third Step in the Construction of the Ross Dam “Studies by our District Engineer, Seattle, Washington, indicate that 300,000 acre-feet or more of capacity would be required to control floods comparable to the historical floods of 1851 and 1856, although a reserve capacity of approximately 200,000 acre-feet during the period 1 November to 1 April would have controlled floods of record since 1909.”
1/16/1947 Seattle District District Engineer Corps of Engineer Letter to North Pacific Division, Re: Skagit County Planning Commission Meeting on Flood Storage, Ross Dam, Skagit River, Washington “Several members of the committee objected to the proposed flood control reservation of 200,000 acre-feet from 1 November to 1 April on the grounds that, although the amount of storage was adequate, the period suggested did not include the usual early fall high water in October, nor the snow melt high water in April.  In historic times neither of those high waters has exceeded bank-full stage of Skagit River, and anticipated reservoir operations are such that flood storage reservation in the months of October and April would reduce the prime power output of the plant.  Nevertheless, the representative of Seattle City Light stated that the City would have no objections to reserving 200,000 acre-feet of flood storage from 1 October to 1 May of each year.”
4/29/1947 Federal Power Commission Order Authorizing Amendment of License [to complete Ross Dam] “Upon installation of the spillway gates it is provided that during the period November 1 to April 1 200,000 acre-feet of storage space in Ross Reservoir shall be reserved by the licensee for flood control and utilized as prescribed herein.”
12/27/1948 Seattle City Light Letter, Re: Amendment of License - Project No. 553 - Third Step of Ross Dam Request due to inadequate data, incomplete dam & powerhouse construction and also “the position that the Skagit Project bears to regional power development rather than an isolated project.”
1/26/1950 Col. Itschner Ltr to Seattle Department of Lighting/Seattle City Light on Ross Dam Storage “The value of flood storage at Ross was recently demonstrated during the November 1949 flood when river stages at Mount Vernon were reduced by an estimated three feet through the fortunate availability of sufficient storage above Ross Dam.”

See Also: 1/7/1950 Reply to Corps Request for Flood Fight Mapping: At “the peak of the Nov. 27-28 flood... The dikes at Mount Vernon were about 1.5 or 2 feet above the peak at most places, with weak spots developing near Avon.”
2/8/1950 Corps Seattle District Ltr to North Pacific Division, Re: Standard Project Flood, Skagit River Basin, Washington “From the hydrograph on Plate 4 and considering 200,000 acre-feet available in Ross Reservoir for reduction of floods, it is calculated that the peak inflow of 97,000 second-feet could be reduced to a constant outflow of about 25,000 second-feet. The Skagit River Report may present data to indicate that a reduction to zero outflow for a short period may be better for flood control, but in any case it is evident that the Ross Reservoir, will be able to accomplish a substantial reduction of flood flows.”
7/17/1950 Seattle City Light/Department of Lighting Letter to Corps of Engineers, Re: Costs of 200,000 Acre-Feet of Ross Dam Storage & Discharge Capability Past Gorge Diversion Dam “The Department has made a study of the operations of the reservoir to effect flood control in the amount of 200,000 acre-feet to be made available continuously from December 1 through February 15 of each seasonal year. In this study it was assumed that the Skagit River plants would be operated as a part of the Northwest Power Pool.” 
8/13/1953 Ltr to USACE Corps District Office in Portland fm USACE Seattle District Office re: Flood Control Requirement and Operating Procedure for Ross Reservoir, Skagit River, Wash. This document provides descriptive detail into how the USACE determined to lower the required 200,000 acre feet originally required for flood control storage down to 125,000 acre feet.  “All discharges of more than 65,000 second-feet at either Sedro Woolley (1908 through 1923) and Concrete (1924 to date) occurring in October, November, and December were studied.”

See also: Retyped for clarity and emphasis 8/14/1953 Corps document.