Latest news with #AquiferRecharge
The Hindu
13 hours ago
- General
- The Hindu
WRD, Danish team to launch second phase of project to map groundwater and reverse seawater intrusion in Minjur
Minjur, a locality in the city's northern fringes that has long battled seawater intrusion into its groundwater aquifers, will soon be the focus of an intensive study aimed at assessing the extent of exploitation and exploring strategies for its reversal. With the findings of a pilot study on groundwater mapping in Minjur validated, the Water Resources Department would expand the study along with Danish team in the Minjur belt. The phase II of the project will map the groundwater aquifer and arrest seawater incursion in the locality through Managed Aquifer Recharge (MAR). Officials of the WRD noted that the seawater has moved inland for about 15 km and the water quality has turned saline with a total dissolved solids level exceeding 10,000 ppm in several places. In a first step towards implementing the second phase of the project, the team from Geological Survey of Denmark and Greenland, WRD's State Ground and Surface Water Resources Data Centre and water resources experts discussed the aspects of MAR technology during a recent meeting. For many years now, Minjur residents rely on municipal and private water supply for all their needs as salinity ingress has affected coastal aquifer. 'Water drawn from wells in areas close to Kosasthalaiyar riverbank is yellow in colour. Groundwater is availabe at a depth of 40 feet but it has high iron content. Each family spends a minimum of Rs.2,000 on water every month,' said of Minjur. Noting that water quality has improved in sites along water bodies, residents wanted groundwater recharge projects to be executed on a large scale. Officials of the WRD said a network of 145 borewells would be sunk across 63 villages at various depths and distance to study the salinised acquifer. Every five km would have piezometers with various instruments like digital water level recorders and water quality sensors. The study would be carried out using s-Tem profiler, a geoscanner tool designed to acquire subsurface data and ideal for mapping groundwater aquifers. 'We are planning to concentrate more on the 15th km with three borewells sunk in each chosen site at various depths to assess the groundwater level and quality. This stretch would have 71 borewells sunk for the study,' said an official. Some of the villages to be covered include Amoor, Thachoor, Panjetty, Alamathi and old Gummidipoondi. The Rs.10 crore would help identify potential recharge zones to restore the freshwater balance by pushing salinity back towards the coast in five years. A combination of recharge structures, including recharge shafts, would be established through MAR and identify potential for extraction and recharge, said the official. The project would be scaled up to other over-exploited groundwater zones like Cuddalore and Thoothukudi. Visiting Faculty, Hydraulics and Water Resources Engineering Group, Department of Civil Engineering, IIT Madras, who was part of the discussion, said Minjur belt is covered by data collection network of various government agencies and the new initiative would help enhance the ongoing efforts. Several recharge structures like check dams have indicated potential for harnessing groundwater. Citing his study on seawater intrusion in a coastal aquifer, he said largescale measures like interlinking of Araniar and Kosasthalaiyar rivers with a canal to transfer floodwaters and reviving water bodies are essential. Various measures, including interlinking of rivers, would help decrease the extent of seawater incursion by three km in 2030.
Scoop
09-05-2025
- General
- Scoop
Massive Water Rehab Project Celebrates ‘Win For The Environment'
New Zealand's largest managed groundwater rehabilitation project has been given the greenlight to expand. The community group behind the water improvement scheme in Mid Canterbury is "delighted" it's been given consent to upscale their work to improve groundwater and river quality. More than two years after it lodged a resource consent application, the Hekeao/Hinds Water Enhancement Trust (HHWET) has been granted consent, with conditions, to expand. The Trust said in a statement they were "delighted with this decision to grant the consents, which is a win for the environment'. The group declined to comment further while the independent panel's decision is open to appeal. HHWET applied for consent to operate Managed Aquifer Recharge and Near River Recharge sites at 37 locations, 15 existing and 22 new sites. The aquifer sites contain infiltration basins, which act like big leaky ponds. The basins are filled with high-quality water that seeps down and recharges the groundwater. This enhances ground and surface water quality and quantity. Near River Recharge is the same but is located in a river's flood plain, so that river flow and quality are enhanced. The group wanted to use water from Rangitata Diversion Race Management Limited (RDRML) - a 67km long canal that distributes water throughout the Mid Canterbury region. This required consent to allow the water use as part of the process. The applications were notified in June 2024 and received 79 submissions - nine opposed and the rest in support. Te Rūnanga O Arowhenua opposed the consent application on the basis there was "little rational basis for the Panel to take a gamble on such a risky and ineffective proposal, when the downside for important environments and values is so significant'. Save The Rivers Mid Canterbury also opposed the application as it believed it was better to leave the water in the river, than "use it to cover up the results of intense farm practices'. After a four-day hearing in December, the independent panel sought additional information from the applicants and independent legal advice. The panel released its 114-page decision last week that outlines how the panel believes the opposing concerns have been addressed. The applicants said there would be positive effects on ground water levels and decreased nitrate levels in downgradient waterbodies resulting from the trial, as well as increasing river (surface water) flows and ecological benefits, the decision said. The panel included additional monitoring conditions to provide greater certainty around the outcomes. The panel also noted submitters referenced an economic analysis in 2023 that without Managed Aquifer Recharge, it would be an 'economically catastrophic for Mid Canterbury urban and rural communities'. Submissions touched on the 'unfavourable economic implications' of not meeting targets set through the National Policy Statement for Freshwater Management and Canterbury Land and Water Plan. One of those concerns was that additional water would be taken from the Rangitata River by the RDRML to support the Managed Aquifer Recharge use. The panel determined the consent was about what RDRML's existing allocation could be used for. Hekeao/Hinds Water Enhancement Trust will use what water is available from the existing take. 'There is no take application before us,' the consent decision states. 'The fact remains however that RDRML will take its full allocation of water. 'If the water is not used for MAR (Managed Aquifer Recharge), it will be used for one or more of the purposes specified in RDRML's consent. 'In this regard, we think it unrealistic for those opposing submitters to invite us to refuse consent on the basis that the water should (and would, they say, if consent is refused) remain in the Rangitata River.'
