HomeMy WebLinkAbout1996.09.06 - Howard Street Drainage Corridor AssessmentPolaris Engineering and Surveying, Inc.
206 South Lincoln Street, Suite 201
Port Angeles, Washington 98362
360) 452 -5393 FAX; (360) 457 -9319
September 6, 1996
Pacific Rim Soil & Water
203 Fourth Ave., East
Suite 416
Olympia, WA 98,501
ATTN : Lisa Pilazzi
RE: City of Port Townsend
P93 -0056 - Howard Street Drainage Corridor Assessment
Lisa,
Please find attached two drawings of the wetland. Sheet 1 is at 100 scale and shows
the wetland delineation as surveyed by Polaris Engineering & Surveying. The
wetland has an area of 0.66 acres. The line to the southeast shows the channel
corridor flagging.
The second drawing shows a larger area (no scale) which also depicts the high water
level as measured by CH2M -Hill in March, 1996. While the survey is not complete,
it does show that a large portion of Block 2 was inundated. Whether this area should
be included within the wetland boundary is subject to field verification. It does
suggest that the wetland could be much larger than originally anticipated.
Apparently, no measurements were taken on the north side of Discovery Road near
the Block. 14 alley.
We have just completed a drainage plan for the City of Port Townsend that takes all
of this area drainage and conveys it through a culvert system to 12th & McPherson
Streets. The Motor Addition drainage is conveyed across Discovery Road, through
W.C. Hammonds Addition and enters the culvert system at 12th & McPherson. The
construction contract for this project was approved on September 3rd by the City
Council. We have also completed the design for extending the culvert system from
12th & McPherson to Logan & 8th Street at Bishop Park. One alternative design
provides some degree of biofiitration on 12th Street between Thomas and Logan
Streets.
In 1993, Polaris designed an entrance control device for the Simms Way culvert so
that the road impoundment could act as a dam and the channel as a detention basin.
Although the design was approved,, I do not think that the structure has been
constructed.
In essence, the entire drainage corridor has been designed as a piped system.
Although there appears to be at least three independent jurisdictional wetlands and
one segment of natural channel in the on -line system, there has been no
environmental assessment of the impacts of construction. The wetlands are not
directly affected by the proposed construction, but they will be affected as upstream
development occurs. There has been no consideration given for pre- treal(ment of
waters entering the wetlands.
The EES basin boundary shows the area north of Discovery Road as within Basin 11.
From the topography, it appears that the natural drainage has been altered by the
subdivision west of Eddy Street. Topography suggest that the drainage had been
part of Basin 16. The drainage within the tract forces drainage to Basin 11 through
a series of constructed swales. I am researching the historic drainage to determine
when the diversion took place.
I would like to prepare a map showing Basin 11, the proposed drainage system, and
the wetland areas for presentation to the City. I am interested in hearing your
comments regarding the wetland areas you have delineated in the Howard Street
area. If you have any suggestions regarding the diversion of runoff and remedial
measures, I would like to hear them also. Please contact me if you have any ideas.
Sincerely,
Mike Szatlocky, PE
cc. 95103