Riverside County supervisors Tuesday unanimously approved an additional $1.5 million in expenditures by the Flood Control & Water Conservation District for emergency projects to protect communities at risk of flooding along the eastern boundary of the burn-scarred Cleveland National Forest.
The Board of Supervisors, without comment, authorized district General Manager Jason Uhley to expand the budget for Murrieta-based construction firm KIP Inc. to $3.75 million, up from the current allotment of $2.25 million.
KIP was retained, along with Corona-based KEC Engineering and San Bernardino-based Sukut Construction, in October to fortify canals, basins and other facilities in preparation for storm impacts connected to the Holy Fire last August.
The 23,000-acre arson blaze denuded steep terrain below Santiago Peak, permitting water to flow unchecked onto lower slopes where subdivisions are situated, mainly in north Lake Elsinore and the Temescal Valley.
Mud and debris flows have caused property damage and submerged streets on multiple occasions because of winter rains. Mandatory evacuation orders have also been issued for public safety, most recently during a storm event in mid-February.
“Despite extensive mitigation efforts taken by the county, the district and city of Lake Elsinore prior to the storms’ arrival, the storms have left streets, residential and commercial properties — and critical flood control infrastructure — loaded with mud and debris which must be cleared before arrival of the next storm,” Uhley said. “This is a pattern that will be repeated.”
KIP and the other firms are working on stabilizing and upgrading the Horsethief Canyon Storm Drain, the Leach Canyon Dam and the McVicker Debris Basin.
“These facilities provide flood protection for much of the adjacent communities during large storm events,” according to a Flood Control & Water Conservation District statement. “However, due to the vast burn area in the canyons and the significant loss of vegetation, these facilities are now at risk of being overwhelmed by stormwater, mud and debris during seemingly modest rain storms. A blockage … or damage to the facilities could result in a critical threat to life and property.”
The agency additionally noted that water quality is a growing concern due to mud and debris flowage into the Santa Ana Watershed.
“Nutrients have been detected in the burn area runoff at levels exceeding 60 times natural background levels,” according to the agency. “In addition to protecting the public and property, the emergency work the district is undertaking also reduces the amount of such pollutants that may otherwise reach and impair major receiving waters.”
The Valentine’s Day storm series prompted the board to declare a local state of emergency. Surface streets, as well as residences and other property, were damaged during downpours at the foot of the Cleveland National Forest. But the most extensive damage was to state Routes 74, 111 and 243 near Idyllwild, Mountain Center and Palm Springs.
Engineering firms hired by Caltrans are repairing the highways.
Uhley estimated the total damage from last month’s storms would top out close to $50 million.