LAND FILLS, REGRADES, CREEKS AND
STREAMS

Although topography has been a restraint on
developmental growth and on the direction of this
growth, man has continually resisted these natural
restraints by altering the land and water elements.
Water defined broad areas and delineated boundaries
or edges for this growth whereas hills have directed
the areas of expansion. These factors were limitations
and provided a natural structural framework for
Seattle's growth.

Before the settlers came, tidewater extended to the
western slope of Beacon Hill. Harbor Island, as such,
did not exist, much of the Duwamish River was a
mudflat, and the hills had numerous ravines, creeks,
swamps and difficult natural and topographical
features.

Most of this has changed through time. The city
suicided off the top of several hills to level these
numerous ravines and to fill in the marshy tideflats.

The Ship Canal was constructed to provide access to Lake Union and Lake Washington for cargo and shipping activities. The Denny Regrade eliminated Denny Hill near the Central Business District to allow northward expansion. Extensive dredging, sluicing, filling, and grading operations created Harbor Island and the industrial waterway in order to provide large, flat and easily accessible land for industry, shipping and airport facilities as well as to harness the flood plain of the Duwamish River. The Duwamish was also straightened to reduce the river's navigable length from 13-1/2 to 4-1/2 miles. These alterations were major to the city's form and the process of city alteration of the landscape is still continuing, although on a smaller scale.

The City has encouraged a program of enclosing
creeks and streams in culverts throughout Seattle.
The map indicates most of the streams and creeks as
they were before this effort.

In the city, especially in the north end, there are
numerous small creeks which are not visually
apparent because contiguous property owners have
fenced in and separately landscaped them into their
back yard environment, e.g. Thornton Creek. There is
an increasing concern for the open creeks still in
existence by neighboring property owners who look
upon them as natural assets rather than as water
control problems.

Similarly, recent fill operations in a number of ravines
have called attention to the importance of these in
maintaining the city's ecological balances.

LEGEND

● major sanitary land fill sites

major regrade

 cuts and tunnels

A. 1st Ave. Regrade (Pine to Denny)
1898-1903
110,700 cu. yds.

B. Jackson Hill Regrade
1910
Max. cut - 85 feet
Excavation - 1,810,656 cu. yds.

C. Dearborn Street Regrade
1909
Max. cut - 108 feet

D. South Canal - (Beacon Hill) Proposal
1896
4.9 mi.
Proposed Max cut - 320'
Width at water level 140'

E. Denny Hill Regrade No. 1
1911
Max. cut - 110 feet
Excavation 4,307,000 cu. yds.

F. Harbor Island
1912
398.2 acres
Fill Estimate - 24,000,000 cu. yds.

G. Duwamish Waterway
1912
Dredge Removal - 1,200,000 cu. yds.
Depth 30 feet up to 1st Ave. bridge
Width 500 feet
East & West Waterway 750 wide

H. Lake Washington Ship Canal
1916
Length - 8 miles
Width - 100 feet
Depth - 30 feet
R.O.W. - 300 feet
Lock sizes:
Large 80' x 825'
Small 30' x 125'

I. Denny Regrade No. 2
1930
Max. cut 80 feet
Excavation - 4,197,000 cu. yds.

J. Great Northern Train Tunnel

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