03-20646. Intent To Prepare a Draft Environmental Impact Statement/Environmental Impact Report (DEIS/EIR) for a Permit Application for the River Road Treatment Wetlands Project in the Santa Ana River (SAR) Floodplain Upstream of the River Road ...

AGENCY:

U.S. Army Corps of Engineers, DoD.

ACTION:

Notice of intent (NOI).

SUMMARY:

In compliance with the National Environmental Policy Act (NEPA) of 1969, 40 CFR 1508.22, and 33 CFR Parts 230 and 325, and in conjunction with the Orange County Water District (OCWD), the U.S. Army Corps of Engineers (Corps) is announcing its intent to prepare a draft Environmental Impact Statement/Environmental Impact Report (DEIS/EIR) for the River Road Treatment Wetlands Project (RRTWP), proposed to be located in the Santa Ana River (SAR) floodplain upstream of the River Road crossing, Riverside County, California. The project entails construction, operation, and periodic maintenance of treatment wetlands in the SAR floodplain. The SAR floodplain meets the Corps' criteria for “waters of the U.S.,” and the project is subject to Corps jurisdiction under the Clean Water Act. The affected area also contains Corps-owned lands leased to the Riverside County Regional Park and Open Space District. The area has been designated critical habitat for three federal-listed species by the U.S. Fish and Wildlife Service (USFWS); as such, the Corps will comply with the requirements of Section 7 of the Federal Endangered Species Act.

FOR FURTHER INFORMATION CONTACT:

Daniel Swenson, Project Manager, at [phone] ([e-mail]) or Fari Tabatabai, Project Manager at [phone], U.S. Army Corps of Engineers, Los Angeles District, P.O. Box 532711, Los Angeles, CA 90053-2325.

SUPPLEMENTARY INFORMATION:

1. Background

The treatment wetlands are necessary because of upstream sources of water pollution. The effect of the treatment wetlands would be to reduce downstream water pollution, thereby increasing groundwater potability, aquatic habitat function, and reducing potential human health threats.

Treated wastewater and return flows from irrigated agriculture and dairies are major sources of nitrate loading into the SAR. Nitrate loads enter the river directly through waste discharges and indirectly through surface runoff and rising groundwater. High levels of nitrate are a potential human health threat that can have adverse effects on infants and pregnant women. In addition, formation of algae blooms can lower the dissolved oxygen in the water resulting in fish kills and can form a clogging layer on the bottom of OCWD's recharge basins resulting in a decrease in water recharge and an increase in maintenance requirements.

The Proposed Project is based on the success of OCWD's Prado Wetlands, located immediately downstream of the proposed RRTWP, which has been successful in benefiting the OCWD groundwater basin by improving groundwater quality and increasing recharge rates.

The work would take place on both OCWD and on Corps-owned lands within the Prado Flood Control Basin. The OCWD is the sole project proponent and the applicant for the Section 404 permit. As such OCWD would be responsible for construction, operation, and maintenance of the proposed facilities as well as preservation of existing operational facilities in Prado Dam, which is operated by the Corps. The Corps land under OCWD consideration consists largely of wetlands now in undeveloped recreation lease held by Riverside County Regional Park and Open Space District. The proposed work on Corps land would replace Arundo donax-dominated wetlands with higher quality, native vegetated wetlands. Outdoor recreation amenities including interpretive trails are also proposed.

Other environmental review considerations include compliance with Section 106 of the National Historic Preservation Act.

2. Project Purpose and Need

The purpose of the River Road Treated Wetland Project (RRTWP) is to improve the water quality of the SAR supplies that recharge the OCWD groundwater basin. The need arises from high levels of nitrate concentrations that adversely affect water quality and percolation recharge to the OCWD groundwater basin.

3. Proposed Action

The OCWD proposes development of treatment wetlands in the SAR floodplain as it enters the Prado Basin upstream of the River Road crossing. The RRTWP would treat baseflow diverted from the SAR, primarily for the removal of nitrate, and return the treated water to the river at the point of the present diversion to the Prado Wetlands. Maintenance objectives include: (1) Maintain hydraulic control structures and appurtenances; (2) keep the distribution and collection networks and hydraulic transfers free flowing and clear of obstructions; (3) maintain berms; and (4) control habitat performance by monitoring and taking appropriate steps to ensure that proposed vegetation and habitat types are achieved.

The RRTWP footprint would encompass 430 acres on the flood plain south of the SAR channel immediately upstream from the River Road crossing. All 430 acres meet the Corps' criteria for “waters of the U.S.”, and the project would be subject to Corps jurisdiction under Section 404 of the Clean Water Act. The proposed project site contains Corps-owned lands leased to the Riverside County Department of Parks and Recreation. The area has been designated critical habitat for three federal-listed species by the U.S. Fish and Wildlife Service (USFWS); as such, the Corps will comply with the requirements of Section 7 of the Federal Endangered Species Act. The 430-acre area would be comprised of the following: (1) Approximately 190 acres of treatment wetlands surface area; (2) 40 acres of unvegetated laterals and transfer berms; (3) 100 acres of riparian woodland berms that could be affected by construction; and (4) 100 acres of existing high quality habitat that would be avoided, preserved, and enhanced. Of the above, existing moderate and low quality habitat degraded by Arundo donax would be enhanced to high quality habitat. Also, of the above acreages, approximately 52,400 linear feet (about 10 miles) of riparian forest/water edge habitat would be created or enhanced, including habitat for the southwestern willow flycatcher and least Bell's vireo. In addition, selected access trails totaling about 4.6 miles that transverse the RRTWP would be opened to the public for passive recreation.

The RRTWP would treat up to 150 cfs. The concentration of nitrate in the SAR currently averages about 8 mg/L. At flow rates less than 80 cfs, the RRTWP would be expected to reduce nitrate levels to 2 mg/L or less during the summer baseflow period.

The proposed design plan places the RRTWP on the floodplain south of the SAR channel. This is intended to minimize disturbance to the channel and floodplain by avoiding work on the north side of the channel, construction of multiple diversions, or passing water back and forth across the river.

The proposed RRTWP would consist of five operating units within the 430-acre project area: diversion facility, distribution network, treatment wetlands, collection network, and a fifth operating unit. The fifth operating unit, the integrated River Road Treated Wetland outlet-Prado Wetlands diversion facility, would be a modification to the existing diversion located west of the River Road Bridge that would divert water from the SAR. The distribution network would deliver the water to the treatment wetlands. The collection network would collect the treated water and deliver it to the outlet. The outlet would be integrated with the diversion to the Prado Treatment Wetlands. The integrated River Road Treated Wetland outlet-Prado Wetlands diversion would allow for coordinated discharge and diversion in a manner that would allow for coordinated discharge and diversion in a manner that would not degrade hydraulic conductivity or harm existing aquatic species, and that would retain passage of the Santa Ana sucker through the channel.

Design and construction of the principal treatment facilities, including the diversion, treatment wetlands, conveyances and hydraulic structures, would be expected to take about 24 months until operations could begin.

4. Alternatives Considered

The feasibility of several alternatives is being considered and will be addressed in the DEIS/EIR. Those considered feasible will be analyzed in equal detail to the Proposed Action. The purpose of the RRTWP is to improve the water quality of the SAR supplies that recharge the OCWD groundwater basin. The No Action Alternative would have no improvements, and thus would neither improve the water quality of the SAR, nor improve water recharge into the OCWD groundwater basin. No water quality benefits from nitrate removal would occur and no habitat restoration actions would take place.

Other alternatives that may be considered include: (1) Designing larger wetlands similar to the existing Prado treatment wetlands with less habitat enhancement; (2) designing a smaller or larger wetlands complex; (3) conventional chemical treatment by pumping water through a treatment facility; (4) requiring dischargers along the SAR to denitrify first at existing treatment plants before discharging to the SAR; (5) use of another portion of the SAR; and (6) use of upland agricultural habitat next to the SAR with mechanical pumping.

5. Scoping Process

The Corps' scoping process for the DEIS/EIR will involve soliciting written comments and a public meeting. Potential significant issues to be addressed in the DEIS/EIR include surface water quality, threatened and endangered species, and effects from potential flooding. Comments are invited from the public and affected agencies, including, but not limited to, the Environmental Protection Agency (EPA), USFWS, California Department of Fish and Game (CDFG), Riverside County Regional Park and Open Space District, and others.

Public Meeting: A public scoping meeting to receive input on the scope of the DEIS/EIR will be conducted on August 26th at 7 p.m. at the Norco Board Room/Council Chambers at 2820 Clark Avenue, Norco, California. If you have any questions regarding the meeting, please contact Rick Mendoza, Project Manager for OCWD, at the above address or by calling 714-378-3329, or via e-mail: [e-mail].

Schedule: The estimated date the DEIS/EIR will be made available to the public is November 1, 2003.

John V. Guenther,

LTC, EN, Acting Commander.