Watershed Restoration students constructed four “modified live siltation” structures.  Modified live siltation is a revegetation technique intended to encourage deposition at the inner bend of a channel and aid in the formation of point bars.  Additionally, individual student projects were designed and implemented using techniques the students learned in class.  These bioengineering projects included a brush mattress, a brush box, and the installation of biodegradable erosion blankets, which were through-planted with Carex spp. (basket sedge) transplants.

The earthwork for the project was completed within two weeks during the month of October, 1999.  The project reach remained dry and the work was completed before the expected November rains.  Approximately 900 cm of material was removed from the sandbar and used to reconstruct the right bank.  During the excavation of the sandbar, which was thought to be the location of the original stream channel, old spawning gravel was uncovered and left in the newly exposed streambed.
 
 

The reconstructed right bank and other areas that were disturbed needed ground cover for erosion control and stabilization.  The area needing seed, mulch, and revegetation with native species was approximately .15 ha.  The majority of the area was seeded at 45 kg/ha with the native grass Blue Wildrye (Elymus glaucus).  Blue wildrye is a fast growing bunchgrass with a large, deep root system.  This cool-season grass begins new growth in the fall, even before the rains begin.  Blue wildrye is an excellent grass for reseeding burned and disturbed areas.  The area was seeded with other grasses native to the Arboretum such as Slender Hairgrass (Deschampsia elongata).  Certified weed-free wheat straw mulch was applied at a rate of approximately 3750 kg/ha (1 ½ tons/ac) and at a depth of 30-40 cm.

After the initial seeding of native grass species for erosion control, SWAG and the Arboretum sponsored several community-oriented “planting days”.  On one of these “planting days” over 80 community members volunteered.  These volunteer crews planted native grass plugs and native riparian and upland species that were donated from the Arboretum and local agencies. 

A 10-ft swath of fill soil directly under (parallel to) some areas on the right bank only received seed and mulch.  These areas will later be built up using soil wraps, or filled and graded to a slope consistent with the natural contours of the streambank.  Brushlayers of willow and cottonwood species will be placed between soil layers as the bank is constructed to add further soil stabilization.  Once this upper portion of the right bank is completed, native tree species such as valley oaks may be planted here to eventually provide an overhead canopy that will shade this stream reach.