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HomeMy WebLinkAboutSS4 - Big Canyon Creek Restoration Project - UpdateCITY OF NEWPORT BEACH CITY COUNCIL STAFF REPORT Agenda Item No.SS- 4 October 28, 2008 TO: HONORABLE MAYOR AND MEMBERS OF THE CITY COUNCIL FROM: City Manager's Office Dave Kiff, Assistant City Manager 949/644 -3002 or dkiff @city.newport- beach.ca.us SUBJECT: Big Canyon Creek Restoration Project — Update ISSUE: What's new with the Big Canyon Creek Restoration Project? RECOMMENDATION: Receive and file. DISCUSSION: The Big Canyon Creek Restoration Project has been in the works for about five years, and is close to going to final permitting and construction. The City Council adopted the Mitigation Negative Declaration (MND) for the Project on September 11, 2007. However, a new wrinkle is in the mix — selenium. About Selenium (Se). Selenium is a naturally- occurring chemical element ( #34 on the element chart). According to Wikipedia (and others), trace amounts of selenium are necessary for cellular function in most, if not all, animals — but excessive amounts can be toxic, and the safe level for ingestion varies among the biological species. Selenium can concentrate in runoff as it flows through soils that contain selenium. The runoff process leaches natural soluble selenium compounds (such as selenites and selenates) into the water, which may concentrate in surface waters, wetlands and ponds that receive the runoff. Anthropogenic activities (activities by humans that cause change) such as mining, hydromodification and irrigation can also mobilize and concentrate selenium in surface waters. One of the most famous examples of selenium toxicity was the Kesterson National Wildlife Refuge located in the southern San Joaquin River Valley. Excess agricultural drainage water containing selenium was used to create a series of wetlands. Selenium concentrations in the ponds and wetlands at Kesterson accumulated at high enough concentrations to cause deformities in bird embryos and hatchlings and selenium toxicosis and even mortality in adult birds. As a result, in 1988 Kesterson was closed and the wetlands removed. Big Canyon Wash watershed is a two- square mile watershed that is tributary to Upper Newport Bay. The 60 -acre Nature Park is located at the downstream end of the watershed. Perennial flows in the creek support a riparian corridor along the creek and two freshwater marshes within the nature park. A small, somewhat ephemeral marsh is located near the upper end of the park, Big Canyon � eek Restoration Project Update October 28, 2008 Page 2 and a freshwater pond and wetlands is located at the downstream end of the park. Surface waters in the creek collect in the lower freshwater pond area before flowing into Upper Newport Bay (see Diagram #1). Recent testing (since July 2007) done by the City's contractor as a part of the Big Canyon Creek Restoration Project's environmental and hydrologic analysis has shown that the creek and freshwater marshes have excessively high levels of selenium, which exceed water quality standards, and endanger wildlife and aquatic life. It is uncertain what the sources of the selenium are, though one possible source is the area's adjacent hillsides that contain rock formations that have been known to contain naturally high levels of selenium. This selenium may become mobilized by surface runoff during storm events, irrigation, and groundwater. Selenium can then become concentrated in surface waters and can bioaccumulate in algae, plants, invertebrates, insects, fish, and birds. Animals bioaccumulate selenium primarily through what they eat. Diagram #1 Two Paths Towards Fixing the Problem. Selenium concentrations in Big Canyon Creek Wash have been identified as an environmental problem; this problem must be fixed. It is not an option to ignore the high selenium concentrations in the creek, in part because the concentrations of selenium in the water, sediment and biological species in Big Canyon requires the California Regional Water Quality Control Board, Santa Ana Region (Regional Board), through the Clean Water Act, to adopt a Total Maximum Daily Load (TMDL) for the Creek. Therefore, there are two paths to addressing the selenium problem — first, to continue with the proposed Big Canyon Creek Restoration Project and consider the mitigation measures shown below within the context of the Project. Because the Project itself would remove the existing lower freshwater pond, replace it with a saltwater marsh and tidal mudflat, and would create two new freshwater ponds further up in the Wash (please see Attachment A for a diagram), the Big Canyon G k Restoration Project Update October 28, 2008 Page 3 combination of the Project and the mitigation measures would likely help to solve at least part of the problem. Note that we can expect that the Restoration Project's new freshwater ponds would likely have the same problem with selenium as the existing pond if we do not build -in mitigation measures to prevent the problem. These mitigation measures include: 1. Providing a non -creek source of water for the new freshwater ponds such as potable water, provided that the concentration of Se in the potable water is below five parts per billion (Newport Beach's water has been averaging less than 5 ppb); 2. Diverting creek water away from the new freshwater ponds, including during storm events; 3. Investigating the upstream and outside sources of selenium. ; 4. Excavating the existing freshwater pond to a depth that removes the high selenium sediment, and possibly using that sediment as fill for a dry area of the Project, such as the Interpretive Area. Remember, selenium is only a concern when it undergoes leaching; or 5. Removing the freshwater ponds entirely from the Project. This is a less than desirable option to our resource agency partners, including the California Department of Fish and Game (DFG), whose funding arm is the Wildlife Conservation Board (WCB). The agencies may insist that the current freshwater pond's valuable habitat be replaced in some manner to attract the Western Pond Turtle. The 2nd path is to suspend the Restoration Project and start an entirely new effort that solely focuses on remediation of selenium in the existing degraded ecosystem. It is likely that the Regional Board would direct us to do this via a TMDL if we were to stop the Restoration Project and not do anything else. Staff does not recommend following this path. Recommended Path. The discovery of selenium in Big Canyon Creek poses the following challenges and opportunities for us: • We have secured more than $2.3 million in funds for the Project. These would be matched with a similar amount from the WCB. The total cost of the Project, before the selenium discovery, is estimated at $3.7 million - $4.5 million. • The WCB has this Project on its list of projects to be funded, but we cannot wait much longer to construct the Project because the WCB's funds are bond funds (from Propositions 40, 40, and 84). • Now that we've discovered the selenium, we need to act on it — doing nothing (including abandoning the Restoration Project) is not an option. The Regional Board is required to adopt a TMDL for Big Canyon to address the existing levels of selenium. This project would aid in reducing the selenium in Big Canyon Wash and would help to eventually bring the creek into compliance with water quality standards. • The Regional Board can also be expected to ask us to study this issue more comprehensively — that means source - tracking the selenium upstream and providing geotechnical borings at the locations of the proposed freshwater ponds. Sampling, testing, and analysis for this effort — along with a concept plan to address the problem — is in the ballpark of $220,000 (including contingency). • Selenium is a challenging element to remove — indeed, for the past 3-4 years, the City has participated in a regional working group on selenium removal in the San Diego Creek Big Canyon .. eek Restoration Project Update October 28, 2008 Page 4 watershed (the Nitrogen and Selenium Management Program or NSMP). Inexpensive and effective solutions are hard to find within that process. We are hopeful that the Working Group may have a source of funds for some of the costs identified in the bullet point above. The MND has already been issued for the Project — it didn't specifically address some of the mitigation measures identified in the previous section. The City's intention going forward reflects Path #1 and is.as follows: • Commit to addressing the selenium problem in the context of the Restoration Project; • Attempt to keep the Restoration Project on schedule by incorporating at least mitigation measures #1-4 above into the design; • Working with the Regional Board, DFG, the Coastal Commission, the Coastal Conservancy, and the Big Canyon Country Club to appropriately address the selenium problem, which would likely include the testing protocol discussed earlier; • Consider phasing the Project to secure available funding and begin construction on the non - pond areas of the Project, while completing any additional environmental documentation (likely to be a revision and 30-day recirculation of the MND) that addresses the selenium discovery and incorporates our proposed mitigation measures; • Continue to seek construction funding from the WCB; and • Prepare for the bidding and construction (as noted, possibly in phases) of the Project. This Study Session item is informational and does not ask for specific direction from the Council. However, the Council's questions and general comments on the proposed direction by staff (Path #1) are welcomed. Environmental Review: The City Council approved the Big Canyon Creek Restoration Project's MND on September 11, 2007. The mitigation measures in all likelihood will require the reissuance and 30 -day recirculation of the MND, because neither the presence of selenium nor the mitigation measures were known at that time of the initial issuance. Public Notice: This agenda item requires standard Brown Act notice. Submitted by: Dave Kiff Assistant City Manager Attachment: Revised Grading Plan Revised Grading Plan — Big Canyon Creek Restoration Project