ST9905-CS040511Su'z~n T~)lor - coppell, Tribui~ry G-1-modification, permit ~pplication infon~ede~- ~ i
From: "Loretta Mokry" <loretta@apaienv.com>
To: <ccbond@transystems.com>
Date: 5/11/2004 10:25:55 AM
Subject: Coppell, Tributary G-1 modification, permit application infoneeded
Craig,
The following is a list of specific questions from Jessica Napier
(USACE project manager) that I need information from you and Michael
Hobbs to be able to address:
1. Change in elevation of the stream bed from existing to proposed
(shown on profile views but after talking with Suzan, know this may be
changing again due to constraint of sanitary sewer at Bethel Rd.) Also
what is existing overall slope versus proposed slope? Jessica's concern
is potential adverse effect to water surface elevation (slope) resulting
in change in water velocities downstream.
2. Size of base flow channel and relative size (or relationship) to
bank-full channel flow. We have a 5' width shown for the base flow
channel but no depth shown yet. Channel depth was about 2' on April
29th when I was at the site with Jessica. Do you think a 2' depth for
the base flow channel would be adequate? What would the channel forming
flows (and velocities) be for a 1-3 year frequency storm?
3. Jessica requested specifics on velocities; existing flow volume and
rates as well as projected with proposed channel design. Jessica
referred to channel design to get sediment balance (referenced "Lanes
Balance" pg. 2-19 of Stream Management by J. Craig Fischenich and Hollis
Allen). Her specific concern was related to change in sediment load
resulting in adverse impacts to downstream reaches if the channel is not
designed correctly.
Below are the links to the manual and article Jessica handed me in the
field. I have also included the link to the USACE Fort Worth District
Regulatory Branch web page (which Jessica nows maintains). There are
other links through their web page that may be of interest as well,
especially under the Stream Information Links
USACE web page
http:l/www.swf.usace.army.mil/pubdata/environ/Regulatory/index.asp
"Technologies for urban stream restoration and watershed management"
from Ecosystem Management and Restoration.
http://www.swf.usace.army.mi~/pubdata/envir~n/Regu~at~ry/~thed~inks/stream/techurbanstreamrest.pdf
Stream Management by J. Craig Fischenich and Hollis Allen, Water
Operations Technical Support Program, March 2000
http://www.swf.usace.army.mi~/pubdata/envir~n/Regulat~ry/~thed~inks/stream/ERDCStreamManagement.
pdf
Thanks,
Loretta
' Su::an Ta~,lor - Copp_ell, Tributar,/G-1 mQdification, ._permit app_lication_ info~eeded Page 2
Loretta E. Mokry
Senior Environmental Scientist
Alan Plummet Associates, Inc.
1607 Todd Trail
College Station, Texas 77845
(979) 694-7619 home office
(817) 845-3280 cell
(979) 694-7619 fax (call first)
Through Arlington office
(817) 461-1491
(817) 860-3339 FAX
<loretta@apaienv.com>
www.apaienv.com
CC: <staylor@ci.coppell.tx.us>