[letterhead]801 Union Trust BiogJuly 29th 1907.My Dear Prof MuirYour letter of the 26th inst is just received It is not possible for me to give you maps of the reservoir, but I can give you a full description each. In Lake Weaver the dam will be about 1/4 to 1/3 mile below the out-let of the present [lake?] & the surface of the lake when the [dam?] is full during all months except late Sept. Oct Nov. & Dec. will be about 1 1/2 greater than present area. In Hetch Hetchy the dam will be in the gorge at lower end of valley and will back water nearly 3 miles with an average moth of about 1/4 mile covering I think 1700 acres. The maximum height will be nearly to the base of the falls on the north wall. The lake will be full or nearly so during those months when the mountaineer can visit the region. The dams should be of [rustic?] [illegible] faced masonry & practically a part of the enclosing walls, in no way det[illegible]ing from the surroundings & not reaching with b[illegible] water the great canon [diacritic] which is the feature of the region.Sincerely yoursMarsden Manson.03897
Original letter dimensions: 28 x 21.5 cm.
Reel 16, Image 0851
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