Post-Harvey Project Summary – Hagerson Road Watershed Interconnect

Updated: July 27, 2023
Project Name Hagerson Road Watershed Interconnect
Short Project Description Construction and installation of a 48-inch diameter stormwater line along Hagerson Road with a valve that can be opened under certain emergency conditions to transfer excess stormwater between the Steep Bank Creek watershed and the Snake Slough watershed.
Additional Technical Information A watershed is an area where all rainfall falling within the boundaries of this area drains to a particular stream/ditch/river. For example, the Steep Bank Creek watershed is defined by all rain water that falls and drains to Steep Bank Creek (SBC) which then eventually flows to the Brazos River under gravity conditions. When the levee gates are closed due to high river levels, storm water runoff from this watershed needs to be pumped out of the levee system to the river by the SBC pump station. A similar description can be applied to the Snake Slough watershed. These two watersheds are hydraulically independent, isolated by the natural topography of the terrain within Riverstone and the underground storm sewer system that serves each watershed. This means water from one watershed does not have a natural path to the other during a rain or flood event.  During extreme rainfall events where street flooding is occurring throughout the community, the watershed boundaries can become blurred.

The proposed Watershed Interconnect Project connects the Steep Bank Creek watershed to the Snake Slough watershed with a 48” diameter underground storm sewer line. This pipe will have a valve that is normally kept closed.  This pipe can provide additional drainage capability to either watershed in the event that one system has surplus capacity to accept or pump out water.  It also provides redundancy to the Snake Slough pump station and the Steep Bank Creek pump station, should an unforeseen event cripple one of these two pumping facilities.

This interconnect is designed to have a capacity to move about 30,000 gallons per minute of water from one watershed to the other.

Total Project Cost (including engineering and contingency) $1,702,089
LID 19 Cost (if Project Costs will be shared) and Sharing Basis The storm sewer located along Hagerson Road would have been built to service that road by FBCMUD 149. The associated oversizing of that storm sewer line and its extension is shared equally by FBCLID 19 and FBCLID 15 as it provides equal benefit to the associated pump stations and watersheds. Therefore, the project is proposed to be shared as follows:

LID 19: $441,075

LID 15: $441,075

MUD 149: $819,939

Schedule & Project Status Completed
Financing Source Project has been funded through LID 19 Bonds with a plan of financing that is projected to not increase current LID 19 tax rates.