Environmental

Rockwater Projects

Environmental

Representative Projects

API Management - Hardey Project Subterranean Fauna Investigation

API Management investigated development of a major iron ore project in the Pilbara region of Western Australia. Rockwater designed and undertook a subterranean fauna sampling programme to assess potential impacts to stygofauna and troglofauna for project environmental approvals. A pilot study, followed by six phases of sampling, identified a diverse stygofauna community in the aquifers of the Hardey Project.

 

A programme of targeted regional stygofauna sampling confirmed that alluvial aquifers surrounding the project were considerably more diverse than the fractured rock aquifers sampled within the Hardey project area. Rockwater's investigations confirmed that many of the stygofauna species recorded at Hardey were present beyond the modelled zone of mining influence on groundwater levels.

 

Troglofauna were also recorded at Hardey, in both the Brockman Iron Formation and the Marra Mamba Iron Formation. Through regional troglofauna sampling and interpretation of geological maps and data, Rockwater demonstrated that many species had broader distribution ranges and also that continuous troglofauna habitat existed in adjacent parts of the Hardey Syncline. Rockwater's work provided evidence to regulators that development of the project was unlikely to affect the biodiversity of troglofauna or stygofauna.

 

 

Alcoa of Australia – Risk Assessment of Potential Impacts to Groundwater - Dependent Ecosystems (GDE) within the Spectacles Wetlands

Alcoa negotiated with the Water Corporation to take treated wastewater from the Kwinana Wastewater Treatment Plant (WWTP) over the summer months, as an alternative to increasing groundwater extraction. Historical infiltration of treated wastewater from the WWTP into the superficial aquifer had artificially elevated water levels within The Spectacles Wetland, a conservation category wetland on the Swan Coastal Plain. Rockwater was commissioned by Alcoa to determine the effect that reduced infiltration from the WWTP would have on water levels and GDE within the wetland. Rockwater completed a hydrogeological and environmental assessment using a detailed numerical model of the aquifer system and desktop assessment of the ecosystems present in the study area.

 

A range of extraction scenarios were simulated to predict changes in water levels; the rate and magnitude of those changes were used to assess potential impacts to vegetation communities. A risk matrix was used to determine a level of risk for each category of groundwater dependent vegetation. The assessment determined that the majority of the sensitive ecosystems were at a low risk of impact and key environmental values of the site could be maintained.

 

 

Aviva Corporation Ltd - Central West Coal Project Stygofauna

Aviva is investigating development of the Central West Coal Project located about 10 to 20 km south of Eneabba. The development will require construction of an open pit to extract coal from the Cattamarra Coal Measures and dewatering operations to enable the mine to extend below the water table.

 

Rockwater conducted a stygofauna survey of bores in and around the project area for the purpose of identifying whether stygofauna are a relevant environmental factor for the project, and to identify any conservation-significant species within aquifers likely to be impacted by the implementation of Aviva’s proposal. The stygofauna investigation was designed in conjunction with a hydrogeological investigation of the Central West Coal Project, so that bores being constructed for groundwater monitoring would be suitable for stygofauna sampling. The sampling programme was reviewed and approved by the Department of Environment and Conservation (DEC) prior to being implemented. A total of 96 samples were collected over 4 seasons from 61 bores using pumping and net haul techniques.

 

 

Tiwest Pty Ltd - Jurien North and Cooljarloo Botanical Surveys

Tiwest is exploring prospective tenements for mineral sands in the Jurien area located 18 km northeast of the town of Cervantes. Rockwater was commissioned by Tiwest to conduct a botanical survey over exploration tenements to assess the conservation value of remnant native vegetation likely to be disturbed as a result of the proposed drilling programme and to identify whether conservation significant flora or vegetation is present within the area. Specifically, the presence of any Declared Rare Flora (DRF), Priority listed or undescribed flora species was noted and broad habitat descriptions of areas likely to be impacted were made.

 

Site descriptions were made for each of the vegetation communities encountered during the survey and characteristic/dominant species within each were noted. The presence of any significant (Priority listed, Declared Rare or undescribed) flora was recorded. Where populations of the significant species were encountered during the surveys, counts and habitat descriptions were made and voucher specimens were collected in accordance with DEC flora licensing requirements. Additional specimens were taken for undescribed taxa or for those not readily identifiable in the field. These were lodged at the WA Herbarium together with the appropriate details. A similar botanical survey has been carried out for Tiwest at its Cooljarloo Mineral Sands Mine operation north of Cataby.

 

 

Water Corporation - Waste Water Treatment Plants

As one of the Water Corporation's principal groundwater consultants, Rockwater conducts many hydrogeological investigations for the siting and operation of waste water treatment plants around the State. The infiltration capacity of each treatment plant is assessed in conjunction with the hydrogeological setting through review of existing data and specific site investigations. Site investigations can include falling head tests for determination of infiltration properties, exploration drilling and monitoring bore construction, lithological logging, and sieve analyses. The results from the site tests are used to determine the hydraulic characteristics at the site. Numerical groundwater modelling is then conducted to assess the potential impact of the infiltration of treated wastewater, including groundwater mounding and possible surface seepage, and the fate and transport of nutrients such as nitrate and phosphorous. The results are used in the design of the treatment plant and water reuse schemes.

 

 

Grange Resources Ltd - Southdown Stygofauna

Grange Resources is developing its Southdown Magnetite Project near Albany in the south coast region of Western Australia. As part of its environmental impact assessment (EIA), a stygofauna sampling programme was carried out to investigate whether stygofauna are present in areas of the project footprint, and to address the hydrogeological aspects of the project as they relate to the conservation of stygofauna.

 

Sampling was undertaken at 74 sites in total, across two general localities in three phases. Phase one included regional farm and domestic bores in the area. Phase two focused on groundwater exploration areas along a proposed borefield alignment. Phase three investigated in-pit areas at Southdown and regional areas surrounding both the Southdown project and the proposed borefield. The results of the stygofauna sampling programme were used in conjunction with a groundwater model to delineate areas where impacts to stygofauna habitat may occur as a result of groundwater level drawdown.

 

Western Areas NL - Spotted Quoll Stygofauna

Rockwater was commissioned by Western Areas to conduct a stygofauna survey in the vicinity of its proposed Spotted Quoll nickel deposit for the purpose of identifying any conservation significant species within aquifers which might be impacted by mining operations. A programme was implemented which included the drilling and casing of 16 stygofauna monitoring bores and casing of 4 existing holes for the purpose of stygofauna sampling. This programme was followed by a comprehensive sampling investigation in-line with EPA guidelines. Both haul-net and pumping techniques were used at 3 and 6 months intervals, to allow for stygofauna colonisation as recommended in the EPA guidelines

 

 

Western Areas NL - Evaporation Ponds

Western Areas is planning to construct evaporation ponds to hold water produced from dewatering of its mines at Forrestania. A hydrogeological investigation programme which included test-drilling and monitoring-bore construction was undertaken in the vicinity of the proposed evaporation ponds to assess the local geology, hydrogeology and depth to water table, and to establish long-term groundwater monitoring sites. Hydraulic testing (slug-tests) was conducted on the monitoring bores to determine hydraulic conductivity in the immediate vicinity of the bores. A MODLOW numerical groundwater model was developed to provide estimates of groundwater-level changes that may result from the operation of the ponds.

 

 

BHP - Beenup Mineral Sands Mine

Rockwater has been involved with the Beenup Minerals Sands project since it commenced in 1994. Initially, Rockwater conducted a detailed assessment of water movement and solute transport between dredge ponds, tailings storages and aquifers to manage environmental issues as mining progressed; in particular the presence of Acid Sulphate Soils. With the closure of the mine, groundwater flow has been monitored and geochemical studies conducted for input into the groundwater model. This has allowed advanced modelling to predict whether sulphate or metals mobilised in groundwater as a result of mining activities will reach the Scott or Blackwood Rivers; the direction of movement and estimated times for possible contaminants to reach the rivers; and the concentrations and loads in groundwater discharging to the rivers.

 

 

Karakin Lakes Horticultural Project

Karakin Lakes is located about 90 km north of Perth, just south of Lancalin. An assessment of the potential effects of groundwater extraction from the Karakin Lakes Horticultural project on the nearby Karakin Lakes system, which has been listed in the Important Wetlands of Australia Directory, was conducted using groundwater flow modelling techniques, calibrated to available pumping and water level monitoring data. Rockwater has been involved in the project from its inception and has supervised the installation of production and monitoring bores, assessed pumping test data, conducted water-level monitoring and groundwater sampling and provided reports for submission to the Department of Environment. In addition, vegetation studies have been conducted at the site to monitor the condition and diversity of flora in the vicinity of the lakes.

 

 

Landcorp - Proposed Oakajee Industrial Site

Landcorp proposed to establish an industrial site at Oakajee, located on the coast about 20 km north of Geraldton. Significant community concern was expressed about the potential environmental impacts of such a site, particularly with regard to contamination of groundwater and subsequent possible flow to the ocean. Rockwater was contracted to conduct a detailed hydrogeological evaluation of the site to investigate and address these concerns. The evaluation included preliminary assessment based on existing data, an extensive site investigation including geophysical surveying, installation of monitoring bores for infiltration testing and groundwater monitoring, groundwater age dating, and data input and assessment. The results were reported to the regulatory authorities and a comprehensive background monitoring programme developed to establish baseline conditions at the site. A three year monitoring programme was designed, implemented and reported by Rockwater.

 

 

Aurion Gold - Paddington Gold Mine

Elevated levels of salinity, some metals, and low pH levels around one of the tailings storage facilities at Paddington Gold Mine were investigated. The results of groundwater monitoring were assessed using time series and contour plots for groundwater levels and water quality parameters such as salinity, pH, and metals. The results were evaluated with respect to bore location, construction details and sampling procedures. It was found that although some seepage of saline water appeared to be occurring at depth, elevated metal concentrations were probably an artifact of poor sampling procedures, and low pH values resulted from geochemical processes occurring in situ with fluctuating groundwater levels. Recommendations were made for improving the monitoring bore network and groundwater sampling programme. Groundwater modelling was used to determine the affect on groundwater levels of increasing the height of the storage facility.

 

 

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