Eurobodalla Integrated Water Cycle Management Strategy

Eurobodalla Integrated Water Cycle Management Strategy
Water sourced from the local bore is likely to have a low pH and be high in iron. The nitrate
value of 4 mg/L recorded in mid-1980s, although high, is still within the recommended
Australian Drinking Water Guidelines. Thus bore water would be required to undergo basic
treatment consisting of aeration followed by filtration. A reticulation scheme based on a
local source would consist of a borefield with at least two bores, a water filtration facility, a
small reservoir, pumping facilities and 50 mm reticulation pipes.
The alternative option of sourcing water from the regional scheme would require a pumping
facility at Batemans Bay, 14 km raising/gravity main, a small reservoir, and approximately
50 mm reticulation pipes.
In both cases no fire fighting provision will be provided in the reticulation pipes.
Provision of Full Reticulated Water Supply
Rainwater tanks can be less reliable than town water supplies and if gutters, roof surfaces
and tanks are not well maintained the resulting water quality may be of a considerably
poorer quality than that from a full reticulated town water supply. A full reticulated system
without the reliance on rainwater tanks would eliminate the need for homeowners to import
water during low rainfall and drought periods, and would provide water that meets the
Australian Drinking Water Quality Guidelines.
Similar to the previous opportunity reticulated water could be sourced from the:
Local coastal aquifer, or
Regional scheme.
In this case the average annual and peak reticulated water demands for the full
development situation would be about 80 ML/a and 0.33 ML/d respectively.
The scheme facilities required for both the source water options would be similar to those
required in the previous opportunity, except the facility and component sizes will be slightly
larger. The provision of larger pipes and facilities enables the provision of urban fire fighting
services at minimal extra cost.
Improved Management of Existing On-site Wastewater Facilities
The seepage from existing on-site wastewater management systems could be reduced by
regularly emptying the contents of the septic tanks and installing monitoring systems to
prevent septic tank overflows and to allow for the ongoing assessment of the integrity of the
tanks.
A single contract could be arranged by the Council or by the community such that the septic
tanks are pumped at set time intervals. This would cover both effluent and sullage
pumpout. The pumpout cost could be evenly divided among the residents. To facilitate
pumping every tank would require a small holding tank or pumpout facility.
This opportunity would eliminate the risk of effluent contaminating the aquifer and
waterways. Potential disadvantages include odours and noise during pumpouts and the
frequent movement of trucks in the neighbourhood.
Enhanced Management of Existing On-site Wastewater Facilities
There are several options available to upgrade the existing on-site wastewater
management systems to achieve greater public health and environmental outcomes. The
first option is to retain the existing septic tank and upgrade the on-site effluent management
system. An example of this would be the replacement of the adsorption trenches with lined
evapotranspiration beds that achieve a higher level of water and nutrient uptake through
plants.
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