PRESENTATION 1558 Presented during Restoration, Creation and Mitigation II, 5/29/2019 1:10 PM-2:50 PM
THE SONOMA CREEK MARSH ENHANCEMENT PROJECT: HABITAT IMPROVEMENT AND MOSQUITO SOURCE REDUCTION IN A SAN FRANCISCO ESTUARY TIDAL MARSH Gillenwater, Dan, Gillenwater Consulting The Sonoma Creek Marsh Enhancement Project, constructed in 2015, was designed to improve tidal exchange and habitat structure and function within a 300-acre tidal marsh at the mouth of Sonoma Creek within the San Pablo Bay National Wildlife Refuge (San Francisco Estuary, California). Prior to project implementation, the marsh routinely ponded water for extended periods following spring tides and storm events when water became trapped in a large topographic basin in the marsh interior and between a series of relict levee alignments. This ponding led to high mosquito production rates and reduced vigor and cover of marsh vegetation, which reduced habitat quality for several state and federally-listed marsh-dependent wildlife species. The problems observed at this site are typical of ‘centennial’ tidal marshes (formed over approximately the past 100 years on accumulated Sierra Nevada hydraulic mining sediments), which lack the extensive tidal channel networks and habitat complexity characteristic of ancient San Francisco Estuary marshes. There is concern that centennial marshes may continue to degrade and revert to mudflat over time, a process that is likely to accelerate with sea level rise. The Sonoma Creek Marsh Enhancement Project, implemented by the San Pablo Bay National Wildlife Refuge in collaboration with Audubon California and the Marin-Sonoma Mosquito and Vector Control District, involved constructing a large channel through the central basin of the marsh, bisecting existing relict marsh channels and connected to Sonoma Creek. The excavation spoils were used to create structural habitat elements, including marsh mounds, high marsh ‘lifts’, and a habitat transition (ecotone) ramp along the adjacent upland levee. Three years following project construction, the site has experienced a dramatic reduction in mosquito production rates, revegetation of nearly 100% of the central basin ‘dead zone’, and an increase in wildlife use of the site. This project serves as an example for addressing similar problems at centennial tidal marshes throughout the Estuary. ■
Management & Applied Science: GIS & Remote Sensing PRESENTATION 1033 Presented during Poster Session & Silent Auction Reception, 5/30/2019 6:30 PM-8:30 PM
ASSESSING SEMI-AUTOMATED WETLAND MAPPING TECHNIQUES AND THE DEVELOPMENT OF THE WETLAND LOCATOR MODEL Hengel, Benjamin, North Dakota State University DeKeyser, Edward, North Dakota State University Access to up-to-date wetland inventories is a vital tool for implementing and assessing wetland restoration and enhancement projects. A large portion of the National Wetland Inventory (NWI) has not been updated since its inception in the 1980’s, hindering wetland conservation efforts. The time consuming and costly processes previously used to update wetland inventories are insufficient especially with the lack of funding. Recent research and development of semi-automated tools within geographic information systems (GIS) software has provided methods for identifying wetland areas. These tools are timely and cost-effective alternatives to previous methodology. This study analyzed the accuracy, precision, and miss rates of multiple tools previously used to map wetlands and introduces a new model (Wetland Finder Model) that applies weights to a layerstack method to improve wetland mapping accuracy and precision. The analysis and methods used in this study would provide highly accurate and precise wetland maps that are timely and affordable to all wetland managers and scientists. The results of the Wetland Finder Model (WLM) and the use of a weight equal to or greater than seven will provide a wetland mapping accuracy of 94.4%, a precision rate of 97.5%, and a miss rate of 33.8%. These results suggest that the WLM would not only provide accurate and precise wetland maps but also allow agency funds to be directed towards implementing more wetland restoration and protection projects. ■
Wetland Science & Practice July Special Issue 2019 253