These dams retain water at a shallow depth over large acreages of cropped or pastured lands. Water is retained for at least two weeks before the water is slowly released. Retaining the water greatly increases soil moisture (ground water recharge) in the flooded area to the benefit of crops and wildlife.

The backflood dam shown here has a cat walk for the farmer to walk on to reach the control valve. The valve is closed to hold back the water. If the water level rises too high, there is a spillway that allows excess water to overflow out of the dam and into the creek below the dam.

 

The adjacent picture is a backflood dam seen from the air. The water stored by the dam covers a large area in the lower portion of the picture.

The above dam is 330 metre long (1000 feet) and 2 to 2.5 metres tall. It is the largest dam of the South Tobacco Creek Project. Technically, because the dam is low, the engineering was fairly simple. The water is held back to hold back the runoff for 2 to 3 weeks. The runoff is then slowly released. This delay and slow release greatly reduces erosion and flooding damage.