Water Treatment Plant Upgrades and Water Distribution System Improvements
Water Treatment Plant Upgrades
The City of Granbury has a three phase plan to be able to provide drinking water for the community and meet the future needs of Granbury’s growing population.
Phase I of the project, which involved the construction of a new Surface Water Treatment Plant that can produce up to 2.5 MGD, was completed in January of 2018. This meets Granbury’s current daily water requirements (approximately 1.5-2 MGD), except on peak demand days (3-3.5 MGD) when water supply from the City’s 34 groundwater wells will supplement demand.
At the May 15, 2018 Granbury City Council meeting, Council approved the $13.5M Engineering Services Agreement with Enprotec/Hibbs & Todd, Inc. to proceed with Phase II of the project.
Phase I: 2.5 million gallons per day – finished January 2018 (read news release)
Phase II: 5.0 million gallons per day – approved to begin in May 2018 (read news release)
Phase III: 7.5 million gallons per day – as needed, based on capacity projections
The Surface Water Treatment Plant upgrades are designed in three phases. Phase one, which is now complete, can produce up to 2.5 MGD (million gallons of water per day). This meets Granbury’s current daily water requirements (approximately 1.5-2 MGD). On peak demand days (3-3.5 MGD), water supply from the City’s 34 groundwater wells will supplement demand.
In phase two, which is in the process of being implemented, additional equipment will be installed in the plant. This upgrade will increase the capacity of the plant to 5 MGD.
Phase three will increase capacity to 7.5 MGD, and will be implemented in the next 20-30 years, depending on population growth.
How the Plant Operates
The floating raw water pumps send water from Lake Granbury into the system, where the treatment process begins. The water travels through a pre-treatment phase in which chemicals and plate settlers assist with the removal of solids and pathogens.
After the chemical pre-treatment, the water travels to the microfiltration system, which removes anything that could be seen with the naked eye from the water. To do this, water is pushed through holes in tiny, straw-like filters, where dirt and other solids attach to the walls of the filter.
The result is called filtrate. It is clean, safe to drink, and meets all state regulations. However, this plant takes the water another step.
The filtrate is then pumped through a semi-permeable membrane, known as a reverse osmosis filter. This process removes inorganic solids, such as salts.
Following reverse osmosis, the water is combined with a percentage of filtrate, and moved into holding tanks. From there, the water is pumped into the City distribution system for consumption.
Water Distribution System Improvements
In conjunction with the water treatment plant project and expansion of surface water supplies, the City must make improvements to its existing water distribution system to allow for the introduction of this expanded water supply into the distribution system.
The project is being designed and constructed in three phases using the Construction Manager At-Risk (CMAR) delivery method.
Planned Water Distribution System Improvements
Scout Camp Pump Station and Distribution Improvements: The Scout Camp Improvements consist of a new pump station, various valving improvements, a pressure reducing valve relocation, and 21,500 LF of 16-inch water line. The water line will run from the Scout Camp Tank site and will tie into the upper east pressure plane at the new location of the pressure reducing valve (along Hwy 377). This improvement will assist in providing water to the east pressure plane, replacing the water that the east pressure plane previously received from the SWATS facility. The various valving improvements at the site will help to prevent the Scout Camp Tank from overflowing. The pressure reducing valve relocation will help prevent high pressures at lower elevations downstream of the pressure reducing valve. This supply of water to the east pressure plane allows the water wells in the east pressure plane to rest or shut off for a period of time. This rest time allows the wells to recharge, which improves the quality of water that is obtained from the well.
Knox 1 Tank, Hospital and Bridge Crossing Distribution System Improvements: The Knox 1 Tank, hospital, and bridge crossing improvements consist of 12,000 LF of 20-inch water line and various valving and piping improvements. Both the hospital and bridge crossing improvements address bottleneck issues in the distribution system. These bottlenecks restrict the flow of water to key elevated storage tanks and restrain the system from reaching a hydraulic equilibrium. Part of the hospital improvements also address low pressure issues located around the area near the existing west EST and the hospital. Line work around the west EST will place the nearby cul-de-sac on the west pressure plane and will greatly help with pressure issues associated with these areas. Piping and valving work done around the hospital will place several fire hydrants from low pressure lines to high pressure lines and increase the fire flow capacities of those hydrants. For this improvement, the Knox 1 Tank portion is considered an alternative within the improvement. The available option of using a 20-inch water line to replace the existing 12-inch water line to Knox 1 Tank will be presented and explained in the alternative discussions below.
Lakewood Hills Distribution System Improvements: The Lakewood Hills tie in improvements consist of 1,500 LF of 12-inch water line, a pressure reducing valve, and some valve opening and closing to isolate the Lakewood Hills area on to the east pressure plane. This improvement targets low pressure and low fire flow issues that have been associated with the Lakewood Hills area. The pressure reducing valve will be used to prevent pressures from reaching too high of a level.
North Elevated Tank Distribution System Improvements: The north EST improvements consist of 50 LF of 12-inch water line and various valving improvements. These improvements will help prevent the north EST from overfilling while still maintaining pressure to the surrounding areas.
Water Treatment Plant Distribution System Improvements: The water treatment plant improvements consist of 350 LF of 20-inch water line to replace an existing 8-inch water line in the area. This improvement aids in the distribution of water leaving the water treatment plant by conveying the water to several water mains along Highway 377. A key feature to this improvement is opening valves that have since separated the north and south pressure plane. This will combine the two pressure planes into one large central pressure plane. The combining of the two pressure planes, along with an upsized distribution line, promotes better water distribution thought the system.
Meander Estates Elevated Storage Tank and Pump Station Improvements: The Meander Estates improvements consist of installation of a 250,000 gallon elevated storage tank and pump station improvements to improve low pressure issues and distribution within the Meander Estates subdivision.
Portions of the project that will be constructed on previously disturbed properties, and/or are located on either City or public rights-of-way. The project should only subject the environment to typical short-term disturbances associated with construction traffic and equipment. Short-term noise pollution is possible, but will be intermittent and temporary.
The project is expected to be completed, including all performance testing, in May of 2018.
The water distribution project is fully funded by the Drinking Water State Revolving Fund and administered by the Texas Water Development Board. The project is fully funded by the Drinking Water State Revolving Fund.
Distribution Improvement Projects Maps
(click the name to open/download the map file)
Aerial Map Project Overview
Scout Camp Transmission Line
New Lakewood Hills Tie-In
Meander Elevated Storage Tank Improvements
Water Treatment Plant Transmission Lines
New 20 in Water Line on Lake Granbury
Knox Tank Water Line
Upgraded Scout Camp Pump Station Improvements
North Elevated Tank Site Valve Improvements