Small ditches and shallow depressions that only have water during wet times are the headwater streams (intermittent streams) of the watershed?
Headwater streams (which make up 75 to 95 percent of streams within a watershed) are some of the most understudied and ignored water resources, despite their importance. The headwater areas, which are often dry throughout much of the year, have far reaching implications to their down steam counterparts and the entire stream system. They are often overlooked or abused and many of the changes that we see downstream in the watershed can be traced back to these vital drainage areas.
Headwaters act as the ecological anchor by providing high levels of water quality and quantity, sediment control, and nutrient and wood debris for downstream reaches. All of these functions make them most vulnerable to human disturbances and land use changes.
When streams are straightened or diverted through underground culverts or concrete ditches, it increases the speed of runoff and water velocities which does not allow for filtration of nutrients and sediments or allow for water to go into the ground for the water table. Streams often become “flashy” with rapid rises and falls after rain events. All of these factors increase the erosive energy that is sent downstream.
Protection and restoration of headwater streams is crucial for water quality, aquatic diversity, and stream habitat. It cannot be overstated that healthy headwaters lead to healthy stream systems.
The Stream Teams publication Channels was the source of this information and is presented by the South Grand River Watershed Alliance.