This project replaced original iron Flap Gates with new Stainless Steel Flap Gates for Flood protection from the Brazos River at the North Pump Station.

This project replaced older technology of using stop logs to slow down water with motor controlled Sluice Gates to prevent flood water from coming into the district.

New Sluice gates were installed along the Brazos River GCWA facility as a second line or protection should the river gates leak or fail.

This project replaced the original flood gates in the district that prevented Brazos River water from coming into the district. A flap gate was replaced on the River side while a secondary protection Sluice Gate was installed on the internal side to be closed if the flap gates leaked.

This project replaced the original flood gates in the district that prevented Brazos River water from coming into the district. A flap gate was replaced on the River side while a secondary protection Sluice Gate was installed on the internal side to be closed if the flap gates leaked.

This project replaced original iron Flap Gates with new Stainless Steel Flap Gates for Flood protection from the Brazos River at the South Pump Station.

Channel 4, located in the central portion of the southern levee system, was initially excavated in 2016 as a dry channel draining a portion of development to the Main Channel.  The ultimate design of Channel 4 would be a series of amenitized lakes.  This project, completed in 2020, amenitized a portion of Channel 4 and widened the remainder of the dry channel to provide additional conveyance and storage.  The channel portion of the project was widened from a 10’ bottom width to a 50’ bottom width for a distance of 2,700’ (0.5 miles).  The widening doubled the conveyance capacity of the channel and increased the storage capacity from 30 ac-ft to 60 ac-ft.

This project was required due to the new Fort Bend County Atlas 14 criteria, which predicts more rainfall in certain events than prior criteria. In order to get this increased rainfall out of the district, a new outfall structure was required along Channel 3 just downstream of Pump Station No. 4. This structure consists of 6 – 10’ x 10’ box culvert barrels through the levee and a second major drainage channel outfall to the Brazos River. This project was designed to take advantage of existing terrain, allowing increased flows to be discharged outside the levee by gravity during non-river events (i.e., when the flood gates would be closed to prevent water from an elevated Brazos River from entering the district).

Channel 3, located in the western portion of the southern levee system, was widened in 2018-2019 from a 10-20’ bottom width to a 50-100’ bottom width. The channel was widened a distance of 10,560’ (2.0 miles) from Channel 3-3 approximately 3400’ west of Sienna Parkway to the south pump station. This increased the drainage and storage capacity of Channel 3 from 195 to 302 ac-ft., which is a capacity increase of 55%.

In 2021, Channel 3 was deepened an additional 5’ to its ultimate depth from Channel 3-3 to the south pump station No. 2 (approximately 2.0 miles) adding another 90 acre-feet of storage to the Sienna South System.  This improvement was required due to Atlas 14 criteria and allows storm water flows to leave the southern levee system at lower elevations.

The 104-lot development located off Bees Passage just west of Sienna Parkway was designed to store stormwater events in 5 lakes during Brazos River events.  This project will convert the Major Drainage Outfall at the southern end of Happy Hollow Lane into a 40,000 gallon per minute pump station that will supplement the existing lake storage during Brazos River events.  This project will allow pumping operations to be sustained throughout the event in order to keep internal water levels as low as possible and street ponding to a minimum.

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This project consisted of replacing 4 existing submersible stormwater pumps with more reliable and easier to maintain vertical turbine pumps.

This project will consist of replacing 4 existing submersible stormwater pumps at North Pump Station No. 1 and 6 existing submersible stormwater pumps at South Pump Station No. 2 with more reliable and easier to maintain vertical turbine pumps.

This project consisted of excavating Phase 2 of the regional storage pond due west and adjacent to Sienna Point in the southern levee system. The excavation of this pond resulted in an additional 180 acre-feet of storage being added to the levee drainage system.

This project will consist of excavating Phase 3 of the regional storage pond due west and adjacent to Sienna Point in the southern levee system. The excavation of this pond will result in an additional 360 acre-feet of storage being added to the levee drainage system.

This project will add additional flow area to a pinch point in the channel system following an updated more stringent criteria from Fort Bend County Drainage District.

This project will improve working areas and access to Pump Stations 1 and 3 in the north and Pump Station 2 in the South.  Improvements include adding concrete pavement access, crushed stone working areas, concrete gator pump slabs, enhanced levee access and access ladders for pump station wet wells.

This project was required due to the increased stormwater flows predicted by the new Fort Bend County Atlas 14 criteria. This new pipe culvert will drain increased flows from the Southern Colony detention pond located just east of FM 521. The culvert has been bored under FM 521 and discharge to the SPLID internal Main Channel at the confluence of Channel 1. This additional 66” pipe culvert will supplement the already existing 30” discharge pipe.

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Additional capacity in the main channel located along Sienna Point at the southernmost levee boundary and Channel 1 that extends north from the Main Channel through Sienna Point to Sienna Parkway is required because of Atlas 14 criteria.  The channels will be widened from a 10’ bottom width to an approximate 50-70’ bottom width for a distance of 13,500’ (2.3 miles).  This will add another 155 ac-ft of storage capacity, as well as conveyance capacity to the system for a capacity increase of approximately 105%.

This project, located near Outfall 2 at the western edge of the Sienna South levee system, adds another 405,000 gallons per minute of pumping capacity to the system during a Brazos River event where gravity drainage from the levee system has been cut off.  This pump station consists of 9 pumps each capable of pumping 45,000 gpm.  Along with Pump Station No. 2 in the south and after completion of Pump Station No. 4 Phase 2, the total pump capacity for the south levee system will be 1.2 million gallons per minute.

This project will add lighting packages at all major outfalls located within the Sienna levee system. This project also includes establishing permanent Center Point 3-phase power to all of the back-up sluice gate motors that were installed in 2019. The locations of these projects include the North Pump Stations 1 and 3, South Pump Station 2, South Pump Station Outfall Structure, Oyster Creek and Long Point Creek North Outfalls, Oyster Creek South Outfall, Outfall No. 2 at the end of Channel 3-3 and the GCWA Sienna Parkway Structure.

Construction of a paved roadway on top of the levee from FM 521 to South Pump Station No. 2. This will allow ease of access to the most critical facilities in the levee system during extreme weather events.