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Water Storage

Construction of any size pond or reservoir to store water requires a permit from OWRD. A secondary water use permit is required to use or divert the water that is being stored. Water storage is generally allowed from November through June. Reservoirs with a dam height of 10 feet or greater and that store at least 9.2 acre-feet of water require engineering plans and specifications that must be approved by OWRD prior to the construction of the reservoir. There is an expedited permitting process for individuals building reservoirs with a height of less than 10 feet and that store less than 9.2 acre-feet of water. Contact Benton SWCD for help.


Ponds provide important habitat for turtles, frogs and many other species. However, warm pond water can impair downstream water quality and aquatic life if the pond is connected to a waterway. Furthermore, ponds can be a liability. Check your insurance coverage to assess the risk. 

Pond Construction

Contact Benton SWCD to find sources of technical and financial assistance for pond construction. Remember to add the time and cost of proper pond maintenance to your budget. Once you have determined the pond purpose and type, you’ll need to evaluate the land for a suitable pond site and investigate the need for permits. Keep a record of the design and construction process. Pond Maintenance Ponds require a great deal of maintenance. Control structures must be maintained. Dikes should be kept clear of livestock and vegetation. Check the state noxious weed list or contact Benton SWCD Invasives Program before planting aquatic species. Aquatic invasive plants and fish alter aquatic ecosystems, outcompete native plants, disrupt native fish and wildlife habitat, interfere with recreational activities and decrease water quality. The careful choice of species you place in your pond will reduce maintenance costs and lead to a healthier pond. If you have trouble with algal blooms, contact a local specialist, such as a reputable nursery that sells aquatic plants, for advice.

Rain Water Harvest

In the State of Oregon property owners may collect and use rain water gathered from impervious surfaces, such as rooftops or pavement, in aboveground enclosed tanks. Harvested rain water can be used for outdoor irrigation or outdoor cleaning of vehicles on private property without a permit. A permit is required in the following situations: When using underground water pipes or tanks. When using any individual tank that can contain over 5,000 gallons of water.

When a tank of any size has a height greater than two times its smallest width. When a tank is placed closer to the property line than the minimal setback requirements. Check with the presiding jurisdictionCity or County – to determine setback requirements. If the collected rainwater is used for anything indoors or for any potable use. If rainwater is collected in a pond for re-use.

How Much Water Do You Need?

Different activities require different amounts of water. Crop irrigation requires roughly 2-2.5 acre feet of water per acre during the June to September growing season. One acre foot is equivalent to 325,851 gallons. The size of the cistern needed will depend on the amount of water available, the quantity you want to collect, and what you plan to do with that water during a specific time frame.

Rainwater Catchment Formula

The rainwater catchment formula will help define how much water is available for collection from a roof.

Square Foot Roof Area x Inches of Annual Rainfall x 0.60 = Gallons of water per year that can be collected and stored in tanks. Key Points for Rainwater Harvest Pre-screen or filter rooftop runoff to prevent excessive sediment build-up or contamination in the tank from the roof. Use screens to mosquito-proof all tank inlets and outlets. Winterize the tank during hard freezes – particularly around the spigots. Never leave a tank completely full during a hard freeze. Any tank will crack if it is full under freezing conditions. Always have an overflow pipe near the top, regardless of how big the tank is. Be sure the overflow is directed away from structures and toward a place that will not cause erosion.