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6.0 Jock River-Ashton Dwyer Hill Catchment: Challenges/Issues

Water Quality/Quantity

Surface chemistry water quality on the Jock River in the catchment declines from “Fair” to “Poor” between the upstream (JR-45) and downstream sites (JR-20). The scores at both sites are largely influenced by frequent high nutrient concentrations and periods of bacterial pollution

Instream biological water quality conditions at the Jock River Ashton-Dwyer Hill sample location aquatic habitat conditions from a benthic invertebrate perspective is considered “Poor” from 2011 to 2015 as the samples are dominated by species that are moderately sensitive and tolerant to high organic pollution levels

Existing hydrological and geochemical datasets and assessments (academic, RVCA, others) are only recently available and/or are not being considered in the characterization of the numerous hydrologic functions of the Jock River subwatershed. Further, there is a dearth of hydrologic information (hydroperiod, groundwater/surface water interactions, geochemistry) about the wetlands that remain in the Jock River subwatershed


‘Natural’ vegetation covers 57 percent of the riparian zone of the Jock River and its tributaries (Figure 55) and is below the recommended 30 metre wide, naturally vegetated target along 75 percent of the length of the catchment’s watercourses

Land Cover

Woodlands cover 25 percent of the catchment and is less than the 30 percent of forest cover that is identified as the minimum threshold for sustaining forest birds and other woodland dependent species (Figure 53)

Pre-settlement wetlands have declined by 55 percent and now cover 21 percent (1713 ha.) of the catchment (Figure 54). Fifty-two percent (896 ha.) of these wetlands remain unevaluated/unregulated and are vulnerable to drainage and land clearing activities in the absence of any regulatory and planning controls that would otherwise protect them for the many important hydrological, social, biological and ecological functions/services/values they provide to landowners and the surrounding community