LOS ANGELES – The U.S. Army Corps of Engineers Los Angeles District reached a decision on the proposed Newhall Ranch Resource Management and Development Plan, which includes substantial avoidance and minimization of impacts to aquatic resources throughout the project area located in northern Los Angeles County. The District’s Regulatory Program completed a Section 404, Clean Water Act permit decision and issued a provisional permit to the Newhall Land and Farming Company Aug. 31 for the Newhall Ranch RMDP.
The provisional permit authorizes permanent impacts to approximately 48 acres and temporary impacts to 35 acres of waters of the United States for construction and maintenance of bank protection (including buried soil cement, grouted riprap, and gunite lining); drainage facilities such as storm drains or outlets and partially lined open channels; grade control structures; bridges and drainage crossings; building pads; and water quality control facilities. Of the total 660 acres of waters of the United States that occur on the site, including 277 acres of wetlands, the authorized project will avoid all impacts to approximately 87 percent (577 acres) and will avoid permanent and temporary impacts to approximately 94 percent of the 277 acres of wetlands on site (260 acres).
As part of the approved project, approximately 70 percent or 8,500 acres of the project area are preserved as natural open space, including the Santa Clara River, Newhall Ranch High Country, Salt Creek Corridor, Spineflower preserves and other areas. By preserving the river corridor in perpetuity, the RMDP will protect an important wildlife movement corridor along the river that will support healthy and diverse wildlife populations, while preservation of the 5,700-acre High Country area will preserve an important regional wildlife movement corridor that links the Santa Susana Mountains to the Los Padres National Forest.
The authorized project includes substantial measures to further reduce direct and indirect/secondary impacts to waters of the United States. These project design features will include additional avoidance of approximately 19 acres of waters of the United States in Potrero Canyon, a revised design for low impact development features that would increase infiltration and retention of storm flows and a revised design for ungrouted boulder rock grade control structures and road crossings with soft-bottom, clear span arch culverts in Potrero Canyon.
As part of the decision, the Corps determined that the authorized project avoided and minimized impacts to aquatic ecosystems to the maximum extent practicable. As part of the development of the additional avoidance and minimization measures, the Environmental Protection Agency, the Corps and the applicant met, conferred and agreed to incorporate the above measures into the project design for the authorized project.
The compensatory mitigation associated with the authorized project will ensure no net loss of acreage or aquatic resource functions and services. The authorized project will require 114 acres of compensatory mitigation (establishment, rehabilitation and enhancement of jurisdictional areas), with a 2.4-to-1 mitigation ratio for permanent impacts to waters of the United States site-wide, and a 6.9-to-1 mitigation ratio for permanent impacts to wetlands site-wide. In addition, the authorized project will preserve and protect in perpetuity approximately 612 acres of waters that are not permanently impacted, including 271 acres of wetlands, and the placement of a restrictive covenant on an additional 119 acres, consisting of approximately 89 acres of waters of the United States and 30 acres of adjacent upland floodplain area in the Santa Clara River immediately downstream of the RMDP area.
To maintain existing functions and services in the preserved and compensatory mitigation jurisdictional features and adjacent upland areas, no new drilling, mining, exploring and operating, storing in and removing of oil, minerals, natural gas and other hydrocarbons will occur through the surface of the above areas or the upper 500 feet of the subsurface and no new or additional surface entry associated with the above activities would occur at the surface. In addition, suitable erosion control best management practices will be installed between any existing oil wells and waters of the United States and the BMPs would be required to be maintained in good working condition until the existing wells were abandoned and remediated.
With the implementation of all the above measures, EPA, in their Aug. 9 letter to the Corps, stated, “The changes provide significant additional benefits to protect human health and the environment.”
“Federal regulations for issuing Clean Water Act permits require the applicant to pursue the least environmentally damaging practical alternative, which would have less adverse impacts on the aquatic ecosystem, so long as the alternative does not have other significant adverse environmental consequences," according to David Castanon, chief of the District’s Regulatory Division.
As part of the permit process, Newhall Land initially requested authorization to impact 93 acres of waters of the United States, including 20 acres of wetlands. With project design modifications, the authorized project impacts 48 acres of waters of the United States, including approximately 5 acres of wetlands, resulting in almost a 50 percent reduction in impacts to waters and a 75 percent reduction in impacts to wetlands (see attached graphic).
"We work with applicants to avoid impacts to lakes, rivers, streams, wetlands and coastal waters, where possible; then we try to minimize impacts. Following those efforts, if any impacts remain, we then focus on developing compensatory mitigation plans to offset those permitted impacts,” said Castanon. “Our mission is to protect the nation’s waters in Southern California and Arizona, while allowing for reasonable development and public infrastructure needs through fair, flexible and timely permit decisions."
The issuance of a permit decision for the Newhall Ranch RMDP represents the successful completion of a decade-long partnership with the California Department of Fish and Game and Newhall Land. The CDFG issued a Master Streambed Alteration Agreement for the Newhall Ranch RMDP Dec. 3, 2010 and the U.S. Fish and Wildlife Service issued a biological opinion June 6 that determined the authorized project will not jeopardize any endangered species or adversely modify any designated critical habitat.