Direct seeding of a specially formulated native seed blend was specified for this 3 ha (6+ acre) site.  A soil test indicated that some areas to be seeded were low in nitrogen.  A slow release, polyurethane-coated fertilizer was to be incorporated into the soil.  Slow release fertilizers are believed to aid the establishment native perennial grasses while ammonium phosphate fertilizers are quick release and thereby provide nutrients to the annuals and invasive types of vegetation.  Hydraulic planting was the specified method of application.  The seeding was not completed until December, which was very late in the year for California.  Straw mulch, applied at a rate of 0.7-0.9 tons per ha (1.5-2.0 tons per acre) was also applied with the intention of preventing raindrop and sheet erosion until the grasses became established.  The straw mulch was “punched in” using a straw punch on the flat areas and tackifier was used to anchor the straw onto the steeper streambanks.

On similar state-managed projects in the past, loose and vague seeding specifications has allowed hydroseeding contractors to provide seed that cost much less.  However, these seeds were often not native to the area and did not produce the desired results, which was to re-establish stands of native perennial grasses while also providing the necessary erosion control.  The seeds specified for this project were required to be native to California.  The seed must have been grown and collected in California only.  The seed was required to have a minimum of 80 percent pure live seed (PLS).  The percentage of seed germination was to include the germination percentage of any hard seed rate for approval.

The seed blend developed for this site was developed after consulting with reputable California seed producers familiar with the area.  The application rate was 13 kg per ha (65 pounds per acre).

To ensure that the proper seed was applied, it was specified that the Inspector and/or Engineer must approve the seed before application.  Additionally, the Inspector was to be present onsite during application, and the hydroseeding contractor was to show the seed invoice (proof of purchase) to the Inspector and/or Engineer prior to application of seed.  The following seeds were used:
 

Species	PLS (lb./acre)	% of Mix
Hordeum californica sp. californica	13	20%
Stipa pulchra (Purple Needlegrass)	9.8	15%
Elymus glaucus (Blue Wildrye) var. Anderson	9.8	15%
Bromus carinatus (California brome)	9.8	15%
Lotus purshianus	6.5	10%
Mellica californica (California Mellic)	6.5	10%
Vulpia microstachys (Six Weeks Fescue)	6.5	10%
Poa secunda Secunda	3.1	5%
Total	65 #	100%

The construction of the new Bendway Weirs made this stretch of Buckeye Creek more stable.  This stability was enhanced with the addition of non-living brushy materials (Composite Brush Siltation Weirs or CBSW’s) which help to increase the probability of successful vegetation establishment at this site.  The new Bendway Weirs slow and direct water towards the center of the stream, while the LPSTP will help prevent scour along the outer bank.  Landward of the LPSTP was a benched slope which needed to be vegetated to further slow potentially erosive water during higher flows.

Traditional methods of revegetation for a dryland riparian site such as this included:

• planting of container grown stock;
• direct seeding of site collected materials and seeding for successive seasons;
• planting pole cuttings of site-collected live materials; and
• installation of fascines or wattles constructed of live plant materials.

Composite Brush Siltation Weirs (CBSW's) were placed on the bench landward of the LPSTP, and live pole cuttings were placed around the keystones.  This configuration combined rough vegetative materials on the bench that will help to slow down the water and allow sediment to settle out.  This new sediment drop out zone will become a seedbed for new plants.  As soils gradually build up adjacent to these brush bundles, there will be enhanced opportunity for native plants to establish on their own.

The CBSW’s are designed to decompose over time, with this decomposition being an investment in future vegetative colonization.  The decomposition of the brush weirs will result in an enhanced microflora community within the soil, creating the right conditions for native plant regeneration in a more favorable growing season.  It is important to get native plants established as soon as possible, however, in order to avoid aggressive weed intrusion.  Brush Weirs are very cost effective compared to higher impact systems and more closely mimic the processes which encourage natural plant succession.