19 - Drainage Presentation - Sandy Creek Upper Tributaries 4 and 6

Home Browse Search

Memorandum TO: Grayson Path, City Manager Robert Vine, Assistant City Manager FROM: Todd Mittge, P.E., City Engineer SUBJECT: Drainage Analysis — Upper Basin of Tributaries 4 and 6, Big Sandy Creek DATE: July 11, 2023 Executive Summary: The City of Paris has drainage challenges throughout the city. This analysis combines 5 months of first-hand observations by the City Engineer and other staff from the Winter of 2023, along with historical data from the last major flood events since 2016 and anecdotal data going back to the 1970's for Tributaries 4 and 6 of Big Sandy Creek. This analysis and its associated recommendations complement the Cobb-Fendley Engineering report from 2016. Please contact the City Engineering Department for a copy of that report. Tributaries 4 and 6 drain parts of the Northeast and Southeast Quadrants of the City of Paris, Texas. Drainage pathways include rooftops, surface drains on city streets, some enclosed drainage systems, grass/dirt lined open channels, concrete lined V-shaped channels, concrete lined trapezoidal channels, and concrete lined rectangular channels. All of the channelized pathways vary in capacity, and may be inconsistent with the amount of flows required of them. A visual illustration of these are shown below. Upon my initial review of the situation, I recommend that the city: 1) Further Explore expanding the sizes of some channels in strategic locations. 2) Clean out the channels of significant obstacles and debris. 3) Build detention ponds in key locations. 4) Utilize city staff to perform this work as soon as possible, contracting out where needed. 5) Continue proper enforcement of drainage detention through our subdivision ordinances. Improve ordinance language where necessary. 6) Conduct Lidar laser survey citywide to capture existing topography and aid in future studies. There are some city properties adjacent to the tributaries where flood overflow detention facilities could be built which will help alleviate flooding downstream. There is also the opportunity to partner with a private property owner to build a larger detention facility near Lamar Avenue. Access is difficult in many areas, but using city crews and strategic access points, we can increase capacity and help reduce the risk of flooding of area streets, residences and businesses.