Clare Pipeline
Clare Valley Water Scheme

Shiraz grapes ready to pick at Armagh in the Clare Valley To see more photos from the Clare Valley: Clare Gallery Background to these notes Until recently I was a public servant. My expertise, if any, is in the groundwater field. Public servants are not supposed to make public comment in the area of their expertise. I believe that this is wrong because who could be better placed to provide unbiased informed comment? But, perhaps more importantly, it is an denial of the democratic right to freedom of speech. What follows is my personal opinion. Also see my page on freedom of speech. For notes on growing trees in the Clare Valley see Clare trees. Background to the pipeline scheme Groundwater of moderate quality is fairly widespread through the Clare Valley. Because of this there has not been the strong need that existed in many parts of South Australia for a reticulated water supply; in the Clare Valley people were able to dig or drill wells on their own properties and, generally, obtain a water supply. At present water is piped in to Clare in the north and Auburn in the south; people in the other towns, Sevenhill, Penwortham, Leasingham, Watervale and Mintaro, have to fend for themselves. By modern standards, though, many of the people in these towns do not have a good water supply; either not of good quality, or of insufficient or unreliable yield. Home Top A reticulation scheme to supply households with a reliable water supply is not, on its own, a payable proposition. However, if large volumes of water can be sold to irrigators, as well as the relatively very small volumes required for domestic needs, then the pipe network could come close to paying for itself. What I see as the major concerns The pipeline will bring up to 8 GL (8000 ML or 8 million KL) of water from the Murray into the Clare Valley each year. In theory this will not result in a net increase in the amount of water taken from the Murray because irrigation licenses for an equivalent amount will be bought up from elsewhere. (This is not as simple as it seems, but I will not discuss it further here.) The main problem is not the 8 GL of water, but the 2500 tonnes of salt per year that will come with it. I should stress that the relatively very small volume of water (and consequently small amount of salt) that would be used to provide householder's needs would pose little problem. Soil salinisation The water will be applied to vineyards by drippers. The vines will transpire most of the water, but will not take up the salt. Either the salt will remain in the soil, at least through the summer, or it will be flushed deeper down by the fraction of the irrigation water not taken up by the vines. If some significant fraction of the irrigation water reaches the groundwater table, then it will cause the water table to rise. If the water table rises to within a half metre or so of the surface then then evaporation, due to capillary flow through the soil, will start concentrating salts in the topsoil. Again, my own opinion is that this will not be a big problem in the Clare Valley because, I believe, in most places the groundwater will drain out into the streams before the water table comes close enough to the surface to present a problem. However, soil salinisation could be a problem in parts of the Hill Valley (a catchment to the east of Clare, considered to be a part of the greater Clare Valley). Home Top Groundwater salinisation As explained above, if 8 GL of Murray water is used for irrigation each year, then 2500 tonnes of salt will be added to the soil or the groundwater. Depending on how one defines the boundaries of the Clare Valley, something like 8000 tonnes of salt comes via the atmosphere, mainly with rainfall, into the Clare Valley each year. Groundwater monitoring records show that salinities are not, in general, increasing at present. This indicates that the amount of salt leaving the Clare Valley, via streams and groundwater flow, equals the amount entering. (A couple of people working in the groundwater field would disagree with this.) If the amount of salt entering the Clare Valley increases by 30% (8000+2500=10 500 tonnes) per year, but the amount of salt leaving the Valley does not increase by the same amount, then there will be a net rise in the total amount of salt in storage, mainly in the groundwater, each year. I believe that it is likely that there will be a little increase in the amount of salt flushed from the soils into the streams and out of the Valley each year. However, groundwater salinity is going to increase until a balance is reached where the increasingly saline groundwater flowing out of the Valley takes with it the increased salt load entering the Valley. It is likely that the average groundwater salinity will have to rise by something like the above 30% before this new balance is reached. It should be stressed that the changes will not effect the whole of the Valley equally, they will be concentrated mainly where, or downstream from where, most of the new irrigation takes place. Parts of the Clare Valley will be adversely affected, parts will be unaffected, and parts may be favorably affected. Salt load in rivers If 2500 tonnes of additional salt enter the Valley each year, then eventually that extra salt will have to be flushed out of the Valley each year. A large part of this salt will enter either the Wakefield or Broughton Rivers.