Diffused Surface Water

Diffuse surface water are waters that travel over the ground as a result of rain or snowmelt, but before it flows into a natural watercourse.

This water is also referred to as stormwater.*

The challenge of determining diffused surface waters impact on a potential farm or garden location is identifying where it flows when it is not present.

In late spring this can sometimes be seen as grass laid down is channels down a slope. In more severe cases it can be seen throughout the year as erosion patterns on the soil surface.The best way to see where diffused surface water runs is to observe a site for an entire year while water is present.

I am also including in this category any seasonal springs that may appear on a site as they would be treated the same as diffused surface water.

Diffused surface water is important to identify for three reasons.

First it may be available for your use in the form of water harvesting earthworks such as swales, terraces, ephemeral ponds etc. You would have to check with your local and state water restrictions to determine if you can use it. Currently in the sate of California, diffused surface water is a grey area, where some court cases have found it to fall under the same restrictions as Surface Water (therefore belonging to the State) and in other cases have found it to not belong to the Sate.

Secondly, just as with surface water, it may pose an access challenge. This is the case on our homestead – we have a wet valley meadow with diffused surface water running 5 months out of the year that a road is being built across to access the farm site. This of course requires more advances road building techniques than just dragging your farms tractors box blade around making a new road; we have to raise the road and install culverts to allow the water to flow under the road and dry the wet area out.

Third, if the diffused surface water is above your farm or garden location it may erode your precious topsoil away! With the incredible rains here in Northern CA this year (35” in 5 weeks alone this winter) we have observed additional diffused surface water that had not been here before. Two small springs popped up on the hillside just above our farmland. These were small enough that they can be captured in a water harvesting swales system to divert and harvest the water while keeping the topsoil in place in our farmland.