- USFS Dry Hydrant Manual (USDA Forest Service Southern Region (R8) R8-TP-19 (PDF, 48 pp., 30MB, Sept. 1993)
What is a Dry Hydrant?
A dry hydrant is a non-pressurized pipe system permanently installed in existing lakes, ponds and streams that provides a suction supply of water to a fire department tank truck.
In rural areas, a lack of water mains and pressurized fire hydrants can sometimes impair a fire department's ability to do its job quickly and efficiently. The success of a fire departments operation hinges on the distance a truck must travel to fill-up and return to the fire. In many cases these fill-up points are often long distances from the fire and the firefighters are unable to maintain an uninterrupted water source at the scene.
The installation of a non-pressurized pipe system into local water sources provides a ready means of supplying water to fire engines.
Planning for dry hydrants involves several considerations and should involve
all those affected so a coordinated effort can take place.
Some factors to consider are:
- Current and future population and building trends.
- Property values protected.
- Potential for loss.
- Fire history of the area protected.
- Current water supply systems.
- Other potential water sources.
A dry Hydrant is more than a collection of "hardware." In any area without water mains and domestic fire hydrants, the dry hydrant concept can provide a simple cost-effective solution to the need for access to water sources without delay.
Dry Hydrant Location and Design
The location of individual dry hydrants is also influenced by several factors.
Maximum distance of travel between dry hydrants. This can vary for several reasons, but one target distance could be one dry hydrant every 3 square miles. This would produce a travel time of about 6 minutes between the water and the fire, assuming an average safe constant speed for a loaded truck of 35 mph.
Ownership of the land. The fire department or other authority should contact the legal property owner to secure written permission to use the water source. If a possible dry hydrant site is along a road right of way, you will need town, county or state approval. In some cases Corps of Engineers approval may also be needed. Obtaining written permission is an important requirement that may take some time.
Depth of water at the source. Careful note should be made about the useful depth of a lake or pond, which is from the minimum foreseeable low-water surface level to the top of the suction strainer (not the bottom of the lake). The low-water mark considers tides, drought, freezing and other effects, such as where the water level is lowered to generate power. The absolute lowest level must be not less than 2 feet, to prevent a vortex or whirlpool, which could allow air to enter the pump and cause loss of pump prime. You may need a minimum of 4 to 5 feet of water over the suction screen and pipe during low water to prevent a freeze-up of the screen.
Making a rough estimate of the water volume in a pond when exact dimensions are not known: If you can visualize the relative size of a football field, use that area as a starting point. A football field contains roughly an acre. Every foot of water would provide about 325,000 gallons. This pond should contain about 600,000 gallons per foot of water.
Composition of the bottom material.For long-term useful hydrant operation, the best composition for the bottom of a lake, stream or pond is sand, gravel or rock or a combination of these. Decaying vegetative matter could clog the suction screen.
Ease of digging. A backhoe will need to get close enough to the water's edge to reach out and dig at least 5 feet below the surface of the water to start the trench.
Protection the connection. A location that is conveniently accessible to fire apparatus may also be exposed to accidents from other passing vehicles. An impact barrier constructed of partially buried posts may be needed to prevent a vehicle from destroying a dry hydrant in a heavily traveled area. Special markings may be necessary to avoid damage from snow plows.
Beware of other utilities in the digging area. You must carefully check for the presence of buried lines and pipes and notify utility companies before you start digging.
Dry Hydrant Advantages
Knowing about a quantity of available water in area streams, ponds and lakes gives an advantage to a fire department only if the water is readily accessible. Soft or obstructed ground certainly limits access. Or, the needed water may be located so far away from where it is needed that a fire department's ability to do its job of fire control is impaired.
Mobile water supply vehicles can move water from distant sources, but the critical factor is whether or not the fire department can maintain an uninterrupted supply of a predictable rate of water at the fire scene.
Installation of dry hydrants into numerous nearby and developed water supplies eliminates the inefficiency and complexity of long-distance water shuttle operations. This arrangement also allows access to water sources from a roadway instead of having to work on soft ground immediately adjacent to the pond or stream.
Dry Hydrant installation
All dry hydrants installed under the grant process will be installed by a pre-selected professional installer.
The actual installation steps are:
Dig the trench.
Start excavating the ditch in the water and complete the entire horizontal section of the trench. Keep the bottom of the trench level all the way to the hydrant. (It is less complicated to maintain a level trench rather than a sloped one, which requires figuring new correct angles of joints.) An important safety rule: No one should ever enter the trench!
Cut the pipe to the desired lengths and assemble. Check dry fit.
Prepare the joints.
Join the pipe sections with glue. Make sure you understand the technique, because timing is important. Use PVC cement; never use all-purpose cements to join PVC pipe and fittings. Joints must be held tightly together until both surfaces are firmly cemented. Do not disturb the joint until initial set occurs, which varies according to the temperature. Above 60 degrees F the recommended time is at least 30 minutes. Pressure test the joint. Only after adequate curing according to the instructions for the particular cement. Do not take short cuts!
If more than 8 feet of pipe is out in the pond, a support bracket behind the strainer is a good idea. Support can be as simple as stacked concrete blocks. The strainer must be above the bottom of the pond so that the strainer holes will not be clogged with mud or other debris. Proper placement is necessary for successful operation of the dry hydrant.
Backfill around the pipe assembly, starting with the riser, which should be covered during this operation to prevent rock and fill from falling into the pipe. Tamp the dirt for rigid support. Mound the fill material higher for more freeze protection.
Cut off the riser so that when you attach the hydrant connection to the riser, the top of the opening of the hydrant connection is lower than the bottom of the pump intake on a standard fire engine. That is, the pump intake must be above the hydrant connection.
Smooth over the disturbed areas, and plant grass seed or other vegetation to retard erosion. Mulching helps the seed or seedlings to get established.
Place a sign to identify the dry hydrant and warn against parking and other obstructions. You may want to paint the cap a reflective color for improved visibility during emergencies. If the exposed PVC is not sunscreen protected, exposed pipe must be painted to prevent chemical decomposition from ultraviolet light.
Maintenance and Training
New installations should be initially flushed to ensure removal of any debris that could be harmful to pumps.
Dry hydrants require inspection, testing and maintenance. More frequent cleaning may be needed at streams and ponds to make sure that silt and aquatic growth do not clog the water intake. Aquatic growth can be a special problem in ponds and in slow-moving water sources.
Hydrants should be tested with a pumper once a year and backflushed as part of training exercises. Pay particular attention to safety-related features, such as warning signs and bumper guards.
Appearance is another consideration. Grass and vegetation will need to be kept trimmed. Repainting will be needed periodically. Maintaining the grounds around the dry hydrant assures better visibility when the hydrant will be needed in an emergency, and it will help keep good relations with the landowner.
Records should be kept of all inspections and procedures. Keep the records available with the maps showing the location of all installations.
- Ready to apply for this grant? Get everything you need from our Grants section.
The Virginia Dry Hydrant Grant Program is funded by the General Assembly using funds from the Fire Programs Fund Bill. The program is administered by the Department of Fire Programs and the Department of Forestry and is assisted by an advisory committee.
The objectives of the program are to:
- Conserve energy by reducing losses from fires.
- Conserve energy by reducing miles traveled to shuttle water.
- Fund the installation of dry hydrants that otherwise would not be installed.
- Conserve processed domestic water supplies in urban and urbanizing areas.
Those organizations eligible to apply for dry hydrant grants include the Fire Departments listed with the Department of Fire Programs.
The funding criteria for the grant review and selection include:
- Demonstrated Need
- Energy Saving Potential
- Cost Effectiveness
- Needed Permits Approved
- Completeness of grant application
The focus of the program is to support new initiatives that would not otherwise occur.
The grant process begins with the grant applications, which are mailed to all volunteer fire departments in the state about the first of February each year. A grant agreement form, site information form, certification form, and property owner agreement letter as well as any needed permits must be submitted with the proposal. If more that one grant application is submitted by a department, the priority must be listed on the site information form (i.e. #1, #2, etc.). Forms may be copied locally for multiple grant requests. The submission dates are on the application and are usually around the end of April.
The grants are reviewed and letter notifies the successful applicants. Upon approval of a dry hydrant grant site, the state-approved contractor will contact the department to schedule a site survey and installation. The grant covers a basic installation consisting of a six inch NST hydrant head, six inch to four and one half-inch adapter, and cap.
Following the installation of the dry hydrant, the property will be returned to a field grade quality as provided for by the contract. This means the ground will be as smooth as possible while utilizing a backhoe, hand raking with the application of grass seed and straw, and hand sweeping of road surfaces. Depending on weather conditions, hand raking may not eliminate all clumps of soil. Any additional reclamation work not stated above and required of the installing agency by the property owner and or fire department will be billed to the requesting party at the rate of time and materials.
Fire departments submit grants based on established priority locations, secure any local permits necessary and obtain the landowner permission. The standard dry hydrant installation is specified and any special requirements or additional cost would have to be borne by the fire department. Communities and homeowner associations can obtain a dry hydrant by working the local volunteer fire departments to obtain a grant.
The dry hydrant project continues to be one of the most valuable and visible programs that can be offered to a community. The Department of Forestry and Department of Fire Programs, along with the advisory committee, are looking forward to continuing to fund and sponsor the Dry Hydrant Grant Program in the coming years. For additional information on the program please contact the Virginia Department of Forestry.
Last modified: Wednesday, 12-Dec-2012 11:22:25 EST