Habitat Plan 2 - Onondaga Lake Partnership

DRAFTOnondaga Creek originates in the southeastern portion of the watershed(Tully Valley) and flows north through the town of Tully, the OnondagaNation, the town of Onondaga, and the City of Syracuse beforeemptying into Onondaga Lake (Figure 2.5). The main stem length is27.5 miles (OCDWEP, 2001). The major tributaries to Onondaga Creekare the West Branch of Onondaga Creek, Hemlock Creek, andRattlesnake Gulf. The creek receives runoff from 43 combined seweroverflows and contributes approximately 34% of the annual flow toOnondaga Lake (OCDWEP, 2001). The lower portion of the creek nearthe discharge point to Onondaga Lake is known as the Inner Harbor.This lower reach of Onondaga Creek is classified by the NYSDEC as aClass C waterway which, as designated by the regulations, is bestsuited for fishing and secondary water contact recreation such asboating (6 NYCRR 701).According to the National Inventory of Dams (http://nid.usace.army.mil),there is one dam on Onondaga Creek (Onondaga Dam) located in theTully Valley. No other dams were identified on this creek.At its headwaters, Onondaga Creek historically received significantsediment inputs from the Tully Valley mudboils, located 13 milesupstream from Onondaga Lake. The mudboils discharge sedimentladengroundwater into the headwaters of Onondaga Creek, primarily inthe form of clay minerals. In 1991, the Onondaga Lake ManagementConference (OLMC) identified the Tully Valley mudboils as a source ofturbidity being discharged into Onondaga Lake. Since 1992, theOnondaga Lake Partnership (OLP) has provided financial support to theUSGS to remediate and reduce the sediment loading from the mudboilsto Onondaga Creek. Today, the sediment loading is only a smallfraction of what it once was. (Kappel and McPherson, 1998; and(Kappel, 2004).At its mouth, Onondaga Creek is enriched with nutrients and suspendedsediment. The creek is also enriched with salt from groundwater springsthat continuously discharge brackish (salty) water to the lower reachesof the creek near Onondaga Lake. A sediment loading analysis in theearly 1990s showed that 57% of the sediment load reaching OnondagaLake was delivered by Onondaga Creek, although a more recent study(Prestigiacomoet al., 2006) has shown that this may have actually beenan underestimate. Thus, Onondaga Creek is the largest external sourceof sediment to Onondaga Lake.Despite its water quality problems, there is interest to restore OnondagaCreek for recreational and ecological purposes. Research is underwayto improve the status of Onondaga Creek, including CSO diversion intoengineered wetlands for additional treatment and the rehabilitation ofriparian areas. In addition, the OLP and Onondaga EnvironmentalInstitute (OEI) conducted a visioning program to advance the planningand future use of this area. This document is available on the SUNYESF web site at http://www.esf.edu/onondagacreek/. Throughcontinued improvement, Onondaga Creek will likely become animportant resource to the community and have positive impacts onOnondaga Lake.PARSONS | Remedial Design Elements for Habitat Restoration 57