WATERSHED RESTORATION

Navajo Bowls are bowl-shaped rock structures that protect headcuts from advancing. Navajo Bowls allow sheet flow to cascade over a rock wall, leaving soils behind, and land in a reinforced plunge pool to reduce scouring into a drainage. This structure holds moisture at the bottom and can create microclimates for plants to thrive. Used where drainages drop from an area of otherwise undisturbed rangeland.  

One rock dams are the go-to structure built in washes and drainages where developing erosion is occurring. One rock dams are one rock high that span the width of drainage, reducing water velocity and depositing sediment as it overcomes the dam.  

Utilizing logs instead of rocks, log sill structures are plugs that completely dam the land. Logs are not very plentiful on Black Mesa and are mainly used for structure building or for heat in homes. If log sills are utilized, resource gathering will need to be in forested areas. Recommended use for log sills are in areas of a high potential for wash out or threaten infrastructure and need diversion.

The best use for media lunas is in areas where sheet flow may potentially evolve into incised channels. There are two types of media lunas to either spread or collect, both to dissipate water velocity in a low-grade slope. Media lunas are one rock high and often have a crescent shape to accomplish spreading or collecting.     

Plug and spreads can be built with dirt, rocks or logs, but their purpose is to plug water from advancing down cutting into rangelands and allow it to spread across a basin or meadow to increase soil moisture across a watershed. Plug and spreads can be used in series to rewet an entire range, which can benefit farmland soil.  

Just like Navajo bowls, rock rundowns protect headcuts from advancing on rangelands. The difference between the two is the shape and the scale at which they are built. Rock rundowns are built to the height of the head cut to allow water to cascade over the structure and into a channel where it meets other rocks to reduce its velocity. Rock Rundowns are more gradual and not as abruptly steep like Navajo Bowls are.  

To encourage healthy streams and washes, inducing a meander may help in creating additional pools of water, slowing flow velocity and encouraging more plant growth with increased sediment deposits. Boulder baffles are one way to divert the flow of a wash towards one side, dependent on material availability. While building a boulder baffle one should consider its effect on the rangeland and where the flow will erode and create a bend where water will pool.  

Rock Walls work to reinforce the bank of a drainage to reduce erosion, protecting infrastructure above. Rock Walls are used in areas where erosion would cause major damage to roads, rangelands and other valuable infrastructure. The rock wall can be incorporated with other structures, like one rock dams, to protect from further damaging erosion. Strong footer rocks are installed at the base, with rocks stacked above decreasing in size.  

Similar to a boulder baffle, boulder vanes use only one straight edge to encourage meandering in a stream. Bounder vanes are placed at 15 to 20 degree angles towards the opposing side of the wash to encourage spill away from the protected bank edge. Boulder vanes are armored on the interior of the angle with more rock material and optionally armored on the downstream side of the vane to increase strength and longevity.   

Beaver Dam Analogs (BDAs) in the semi-arid region of Black Mesa are used sparingly. Straight logs or sturdy branches are hard to source, digging holes to install posts are often labor intensive, and downcutting limbs from Juniper trees pulls away from habitat for local wildlife. Wicker Weirs weave flexible branches between wood posts to create a wicker patter along the bankfull length of a stream. BDAs are not often used on Black Mesa watershed and their efficacy is still to be determined in this region.  

In areas with a high concentration of down logs, one may consider installing log mats to plug a wash or to slow and spread a stream’s moisture. Logs are installed parallel to the stream, ensuring uniform length if possible. Protruding branches not removed from logs will not create a tightly packed structure. Log mats packed tightly will act as a plug, but a loosely packed set of logs will leak and allow water through, slowing the flow of water to allow for continual flow.    

Log vanes are vanes made from a straight log installed in the ground of the wash. Due to the smoothness of logs, more water will spill over the log than a boulder vane. Armoring the downstream edge of a Log Vane is crucial to restrict undercutting and increasing damaging to the wash bed.