Identifying mosquito larvae habitat created by CBNG discharge waters using remote sensing

Abstract

Water disposal methods such as pond storage and in-channel releases that are associated with coalbed natural gas production (CBNG) have increased the amount of standing water in the Powder River Basin, Wyoming. These standing waters have been shown to be potential larval habitats for the Culex tarsalis mosquito, the primary vector of West Nile Virus (WNV) in Wyoming. This paper presents preliminary findings from an ongoing research effort focused on identifying environmental and anthropogenic risk factors for WNV associated with CBNG production. Field research suggests that retention pond design and water disposal techniques may serve as either mitigating or compounding factors for risk. Ninety percent of drainages receiving discharge waters tested positive for C. tarsalis while only 23% of reservoirs showed larvae presence. A GISbased risk model based on field observations for CBNG production areas has been developed and tested in which the primary risk factors are C. tarsalis larval habitat and water disposal mechanisms. Preliminary findings using Landsat imagery show a sharp increase (75%) in potential C. tarsalis habitat resulting primarily from CBNG discharge waters. These estimates, based on large-scale remote sensing data, are a conservative estimator of WNV risk associated with the creation of mosquito habitat in active CBNG production in the Powder River Basin. High resolution imagery (Quickbird and SPOT) has been tested and found to identify habitat regions below the lower limit of detection with Landsat.