As part of the Permanent Erosion Control Program, DOT-HWYS continues to repair areas of erosion along state highways. For this site along Kalanianaole Highway in Kailua, traditional landscaping methods could not be used due to its steep, unstable, and irregular terrain. In order to allow the existing trees, and their root systems to remain undisturbed on the slope, the application of a spray-on high-performance mulch and seed mixture was selected for this site. The high-performance mulch contains a combination of an environmentally safe glue mixed with wood fibers, fertilizer, and native grass seeds. Once the slope is prepared, the mixture is applied using a high-pressure sprayer. In addition to adhering the grass seed to the steep slope, the wood fibers retain moisture to promote seed germination and support the newly sprouting grass as it is establishing growth into the soil. The long-term goal for this site is that the native grasses will be self-sustaining and form a significant root structure that reduces soil erosion from the slope. This site is part of the Slope Improvements for Erosion Control, Phase 7 project that is being managed by the DOT-HWYS Lower Halawa Field Office.

Steep slope prepared for application of high-performance mulch mixture.
Application of high-performance mulch using high-pressure sprayer.
Grass seed sprouting through high-performance mulch.
Significant grass establishment three months after high-performance mulch application.