HomeMy WebLinkAboutCorrespondenceAlan Gibbs - Greens Prairie TrI. & Royder Rd. Improvements
From: Erika Bridges
To: Haeber, Jeff
Date: 7/7/2010 5:52 PM
Subject: Greens Prairie Trl. & Royder Rd. Improvements 'L)1/► SC c L
CC: Cowell, Bob; Gibbs, Alan; Smith, Mark
Attachments: 20100707172414079_1.pdf; 20100707172602150.pdf
Jeff,
I discussed some of the issues from yesterday's meeting with Alan and Carol, and we had a few comments for
your consideration. We understand that this is a CIP project and there are budget and time constraints that we
may not be considering. We are happy to discuss any of these items further with you, but acknowledge that
ultimately you will be making these decisions along with Public Works.
* Are these proposed pavement improvements meant to be a short term solution? If so, when do we
anticipate bringing GPT and Royder up to minor arterial standards? ,F t r, vvT T
* Section 6.F.2. of the Unified Stormwater Design Guidelines states that arterial roads, such as Greens Prairie
Trail (GPT) and Royder Rd., are not to be topped by flow from the 100 -yr desi n� storm" which is "based on the
ultimate development conditions that are projected to exist." We have a FCC -RAS modeled flood study from
2007 by Rabon Metcalf, P.E. showing /stating that the culvert crossing GPT just east of Royder is undersized and
has a history of flooding. (See attached)
* _ahon's eport shows the approximate location of the 100 -yr floodplain to be upstream and downstream of
this culvert crossing. The report also shows that the 109yr water surface elevation is almost 5 feet higher on
the upstream side of the culvert (See attached). I'm not sure what the elevation of the road is at this location,
but the 100 -yr flow may be topping an arterial in this case. Widening GPT and just extending the existing
culvert may or may not be a good temporary solution, but it also may compound the existing drainage issues.
* It looks like Kimley -Horn should probably study the drainage in this area to find out what size the
c I� yerts need to be crossing GPT (east of Royder) and Royder (south of GPT).
* Whether or not we replace the existing CMP should also depend on the condition of the pipe. We typically
require RCP to be installed for public storm sewer in . eas subject to vehicular loadings. If we don't replace
it with RCP at this time, we should make sure tha''•rrlfortable with the condition of the existing pipe.
Mtn r' • /..)05
* We feel that the full street sections should be designed by Kimley -Horn at this time, so that all the issues with
drainage, right -of -way constraints, etc. may be considered now. It s ould •e ote• tia we are . 1 •ettin• a
p.rtial s-cti• . d •arti. p. emen for ;. se Rd. s•u •f T. doesn't sound ike we have a grasp of what
he ultimate roadway cross - section wil ook 1 e. t this point, the temporary plans for Royder Rd. look to have
curb and gutter on the west side (school side) and open ditch on the right. ? (,�.;�.,,,
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* Peach Creek Tributary No. 20 appears to run along the eastern side of existing pavement along Royder Rd.
With future ex•ansion of this road, we will need to look at how this drainage will be handled (remain in roadside
ditch o p ped de and how the right -of -way on the eastern side will be obtained. 2%'ig_
* Should more of the Royder Rd. pavement and right -of -way be shifted to the west onto the Greens Prairie
Elementary site? It seems like the new school has necessitated these improvements, and it may be difficult to
get the full street cross - section later.
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Please let me know if you have any questions or would like to discuss further.
Thanks,
Erika
Erika Bridges, EIT
Graduate Civil Engineer
Department of Public Works
1101 Texas Ave.
College Station, TX 77842
Phone: 979.764.3570
Fax: 979.764.3496
ebridges acstx.gov
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City of College Station
Home of Texas A &M University
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