CVWD proposes to realign and rehabilitate approximately 3,400 linear feet of the existing East Side Dike (Dike) beginning at the Dike’s intersection with Wasteway No. 3 and continuing in an easterly direction ending at the Dike’s intersection with Dillon Road. In the existing condition, the proximity of the Dike to the Terra Lago development prohibits CVWD maintenance equipment from accessing the toe of the Dike. Additionally, it was discovered that a portion of the Dike adjacent to the Terra Lago development is not within CVWD’s right-of-way and is on a private property. Overtime the earthen facility has naturally shifted and settled in minor deviation from its as-built position; primarily due to erosion, sloughing and wind-blow sand settling. The purpose of the project is to realign and make improvements to the section of Dike adjacent to the Terra Lago development to provide CVWD maintenance access to landside slope while also resolving the right-of-way issue.
The earthen material comprising the existing Dike on the subject parcels would be excavated and relocated to the new Dike alignment. This material would be placed on prepared subgrade in lifts and compacted to meet design specifications. The realigned Dike would be reconstructed to meet the original United States Bureau of Reclamation design standards and dimensions, with one exception being that the landside slope of the Dike would be constructed at a milder 3:1 slope to reduce the potential for erosion to convey sediment towards the CVWD right-of-way. A maintenance access road would be constructed near the landside toe of the Dike. A concrete drainage channel would be located along the edge of the maintenance access road to convey stormwater to the west for discharge into Wasteway No. 3 and to the east for storage and infiltration in a new stormwater detention basin. A concrete pad would be installed adjacent to Wasteway No. 3 to better facilitate vehicle turning onto an existing access ramp to the top of the Dike. The existing ramp will be improved by placing a 3-inch-thick layer of aggregate base to provide a stable driving surface.
A total of roughly 81,000 cubic yards of cut from the existing Dike footprint is available on the subject parcels. A total of roughly 119,000 cubic yards of fill will be needed for the new Dike realignment. To balance cut/fill quantities a borrow area will be used to supply the balance of 38,000 cubic yards. The borrow area will be located within the work limits just north of the footprint of the realigned Dike.
The temporary work area required for construction is 41.5 acres. Roughly 26.4 acres of the East Indio Hills Conservation Area will temporarily be impacted by project construction under the assumption that the boundary of the conservation area begins at the northern toe of the existing Dike. Construction equipment required at the site includes excavators, dozers, backhoe, graders, concrete trucks, dump trucks, water trucks and utility trucks. Construction is estimated to take approximately 100 workdays. A Cultural and Biological resources report has been prepared for this project. The Cultural Report found the project would have no adverse effect to historic properties. The Biological Report found no special-status plant species were detected during field reconnaissance and the project site is not located within an established wildlife migration corridor, or jurisdictional waters; and the potential impacts to localized wildlife movement would be less than significant. A Coachella Valley Multiple Specifies Habitat Conservation Plan (CVMSHCP) Joint Project Review Process (JPR) is not required for Operation and Maintenance projects. However, CVWD’s Operation and Maintenance Manual for work in conservation areas will apply. Mitigation measures for noise, stormwater pollution and dust control are included in the project specifications as standard Best Management Practices.