One of three photos collectively captioned "Bringing Cedar River water to Seattle. / This shows work in hand by Pacific Bridge Company." The photo is individually captioned "Source of the water supply", so it is apparently a picture of the Cedar River.
Book edited and compiled by Alfred D. Bowen. The photos are uncredited, although <a href="//commons.wikimedia.org/wiki/File:Laying_pipe_for_Seattle_water_supply_02_-_1900.jpg" title="File:Laying pipe for Seattle water supply 02 - 1900.jpg">one related photo</a> on the next page has "Wilse" lettered on it (at lower left). That would be Anders Beer Wilse, so he is probably the photographer of these as well.
1900
<p>p. 114 of <i>Seattle and the Orient</i> (more properly, <i>Seattle …and the… Orient</i>), a 1900 "souvenir" pamphlet edited and compiled by Alfred D. Bowen and published by The Times Printing Company (that is, the <i>Seattle Times</i>).
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Scanned at 300 dpi; images cleaned up using Picture Publisher's "remove pattern" feature.