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After seeing the effects of drought, associated water quality and waterrestrictions in my area I became even more interested in the science ofwater. Arriving at the Maidens Hotel one evening I found a table of waterresources top brass discussing the drought.Thinking about the weight difference between salty and fresh water, I asked

these gentlemen the question: could the river be more saline at lower depthsas a result of saline water being denser? There answer was that this situationwould not exist due to natural mixing!

As it turns out this situation can exist were the river is low and not providingback pressure to the intake of saline ground water into river pockets, orthrough evaporation were reducing water volume increases concentration,fresh water can ride over saline pockets in the right conditions to create thesituation that we later experienced in Menindee after a high salinity pocketof water dislodged from upstream and passed through the town!

During drought periods The Menindee town filtration plant was workingincreased operating periods with occasional problem regarding infrequentshort duration chemistries changes at the plants draw point in the DarlingRiver, reduceing filtration effectiveness on a few occasions.

I became interested in the buffering effects River bank filtration can have onriver water for riparians, and how this might moderate salinity peaks fordrinking water when surface water salinity exceeds desirable levels forpeoples health. Soil filtration has added effects of removing natural organicmatter and can further reduce water pre treatment requirements for humanconsumption through biological processes at the bed/water interface of the

river and through the soil profile. Bank filtration can create a vacuum effectthrough displacement drawing replacement source water mostly all from theriver or lake with good design.

For these reasons I wrote to Broken Hill water explaining the features andpossible merits of River Bank Filtration, my thinking was in suggestion thatRiver Bank Filtration might reduce water treatment requirements or moreexpensive upgrade options for the Menindee town treatment plant as apossibility if required.

In times of high rivers some water can seep through the soil profile to

replenish Ground Waters, a Bank of naturally stored water buffers effects indry periods through hydraulic connections and boundaries in the earth thathave evolved through natural process.

Broken Hill managed aquifer recharge (BHMAR) is a project that I have onlyrecently heard of; even though my town of Menindee and the Lakes are thefocus of this research.

Gary Looney Menindee. NSW. 2879

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On Sunday after the rain I walked along the river to find a drilling rig stoppedin boring position along with a pack of 12 pipes around 12 inches round. 7other bore close by were drilled over a months period. The Bores weremarked Broken Hill Managed Aquifer Recharge, depths ranged from theshallowest at 47 meters with the rest around 80 or more meters deep.

The general water table height around Menindee is 12 to 15m below groundlevel.

Groundwater Storage and Recovery can involve water being pumped into anartificial basin and seeping into the aquifer, in some instance surfacescouring is used to maintain or increase water infiltration rates through thesink area. Alternatively Injection wells place or pump water under pressureinto deeper often more saline aquifers, the water is later pumped up for use!

Operational difficulties can result from microbial growth, chemical

reactions/precipitates through the storage zone or surface interface. Innatural processes Groundwater and source can be some distance apartthrough complex hydraulic interactive connections.Injection well feed water needs to be free of suspended solids andchemically compatible within the process and environment limitations.

Poor Aquifer porosity, material and flow rates can cause excessivegroundwater mounding in the infiltration zone. When surface water is placedinto a more saline Aquifer a fresh water bubble forms and can be shaped bydistrict groundwater extractions, natural water infiltration episodes, andbreaching of Aquifer boundaries.

Changes in water table height can mobilise salt, cause waterlogged soil thatreduces vegetation health or result in saline groundwater entering the river.Water recovery rate can be initially 60 to 80% depending on Aquifer Salinitylevel, material composition and integrity.

You must replace the water taken with interest of losses and absorboperation costs or failure, the water pumped into the Aquifer must be used.Bank filtration should not be thought of as a cheap water works filtration orWastewater treatment option, the latter in regards to not having seweragetreatment in Menindee. Who pays for implementation and running costs for

an Artificial Aquifer Recharge system, who wants it and why are we notdiversifying in efficient water use, decommissioning inefficient horticulturalpractice such as irrigated cotton and rice?

Secrecy in Government and the culture it promotes concerns me because itdenies investigation, scrutiny and input from some interested parties, thatcan lead to damaging, expensive and life threatening outcomes such as theroof insulation program!

Gary Looney Menindee. NSW. 2879

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Fortunately Animals never learnt to make cloths!Figures from CSIRO Darling River Basin Summary, Bureau of Rural Sciences(2007) and Australian Water Resource Council (1987) showed IrrigatedCotton used 54% of all water use. Residential and Commercial/Industrial

made up just 5%. Rural, Irrigated Horticulture and crops made up 26%.

For Example: If we wanted to reduce total water consumption by 1% thiscould be achieved by putting Residents and commercial/Industrial users on a20% Water Cut. Or the same saving could be achieved with just 1.8%reduction in water for cotton production.We could alternatively get the same reduction in water consumption bycutting Rural, Irrigated Horticulture and crop sectors 3.84% reducingproduction and increaseing the cost of local grown healthy food, leading tomore Government costs with isolated people and more nutritional healthproblems.

Gary Looney Menindee. NSW. 2879