Coordinating surface and groundwater supply for resilient communities

Across many parts of the world, the question of how to keep towns, farms and ecosystems watered when rainfall is patchy has pushed planners to look beyond a single source. Communities that once relied purely on dams or purely on bores now find their supplies safest when rivers, reservoirs and aquifers are managed as one connected system. This kind of conjunctive water use blends the flood-recharge responsiveness of surface catchments with the dry-season buffer that groundwater provides.

India's Central Ground Water Board runs the National Project on Aquifer Management to map subsurface storage, identify recharge zones and feed that information into state-level planning. Australian water managers operate at a different scale, but face similar tensions between irrigation demand, town supply and environmental flow obligations in catchments such as the Murray–Darling Basin and the Great Artesian Basin. Both countries share an ambition to align surface and subsurface use so that neither source is exhausted before the next wet season arrives.

In the bush country of western New South Wales, towns like Bourke and Wilcannia have lived through long stretches when the Darling River stops flowing and the town bore becomes the only reliable tap. Further south, irrigation districts along the Murray draw on both regulated river water and shallow aquifer storage, switching between them depending on allocation announcements. These local realities make Australia a useful reference point for thinking about how coordinated rules can keep supplies steady when one source falters.

The following sections look at the practices that help decision-makers treat surface water and groundwater as partners. They draw on hydrological evidence published through the NAQUIM information system, while testing those ideas against Australian experience in shared river basins and outback town supply.

Mapping the resource base before planning begins

Reliable conjunctive management begins with knowing what is actually in the catchment. That means pairing rainfall-runoff models and stream-gauging records with detailed aquifer characterisation, including depth, transmissivity, storage coefficient and the direction of groundwater flow. Without that baseline, planners cannot judge how much water can be shifted from one source to another without damaging the other.

In India's karst terrain, identifying the swallow holes, fractured ridges and percolation zones of the Vindhya range has transformed how recharge is estimated at the watershed scale, and the Vindhya recharge zones overview shows how geological mapping feeds directly into managed aquifer recharge schemes. Similar mapping in the limestone plains of South Australia's Mount Gambier region has guided local rules about where irrigation borefields can expand without drawing the watertable below wetland baseflow levels.

A complete picture also requires seasonal water balance work, since a floodplain aquifer may receive river water for part of the year and lose it to evapotranspiration for the rest. Understanding the volumes exchanged in each direction lets managers set extraction limits that respect the natural recharge cycle, and this kind of accounting is increasingly built into state-level aquifer management plans across India.

Building rules that treat both sources as one

Conjunctive use planning translates that physical picture into operating rules. The core idea is simple: when surface allocations are cut, registered users can draw more from defined aquifer zones, and when recharge is high, the same users ease back on the bores so the storage can recover. The rules need to be written in a water sharing plan, backed by metering, and made available to every licence holder in plain language.

In New South Wales, water sharing plans covering the Murray and Lower Darling regulated rivers already include groundwater sources that interact with the river. Extraction from a floodplain aquifer is tied to a trigger that responds to river levels, so a wet year does not automatically lead to over-pumping once the river starts falling. Victorian arrangements in the Loddon–Campaspe region pair surface water entitlements with aquifer-access entitlements, allowing them to be traded together so that the market reflects the real cost of shifting between sources.

The same logic can apply at much smaller scale. A remote community that depends on a single weir in good years can be given a backup bore with a clear extraction cap, set in the plan, that activates only when weir storage drops below a defined threshold. Writing that rule in advance stops panic pumping and protects the aquifer for the following year.

Storing surplus water underground for drier years

Even with good rules, supplies can fall short in long dry spells. Managed aquifer recharge, where surplus surface water is pumped into suitable aquifers through infiltration basins or injection bores, is one of the most cost-effective ways to bank water for harder years. Aquifer storage and recovery wells do this underground and recover the same water through the same bore when needed.

The Australian experience with the Great Artesian Basin offers a cautionary tale as well as a guide. The Basin Sustainability Initiative funded thousands of capping works on free-flowing artesian bores, which dramatically reduced the loss of pressurised water and extended the life of the resource. In Queensland's Condamine–Balonne area, returned irrigation drainage and floodwater have been injected into deep coal seams and alluvial sands, creating a usable underground reserve that complements the regulated Sunwater scheme.

For Indian states with strong monsoon pulses, the equivalent approach is to route excess canal flow into village recharge ponds and shaft wells during the wet months. The practice works best where the receiving aquifer is confined or semi-confined, and where a downstream monitoring network confirms that the stored water is reaching the intended users.

Monitoring networks that cross the surface–subsurface boundary

A conjunctive system that watches river height and reservoir storage but ignores groundwater heads is flying half-blind. Building a monitoring network that combines stream gauges, piezometers, soil moisture probes and rainfall stations allows managers to see the same event through both lenses.

Telemetry has changed what is affordable. In the Murrumbidgee catchment, automated piezometers installed under the Living Murray program send daily readings back to a central database, where they are plotted against river height and extraction volumes. Indigenous ranger groups in the Northern Territory have begun adding water-quality probes to traditional monitoring walks, feeding results into the same dashboards used by hydrologists. Where agencies cannot fill every gap, citizen science schemes that encourage landholders to photograph farm dam levels and submit readings through a phone app build a wider picture without major expense.

Climate variability and adaptive operating rules

Static rules written for an average climate tend to fail in the years that matter most. Conjunctive management plans need explicit triggers for dry, average and wet sequences, and they need to be reviewed after every major drought or flood event. The Millennium Drought in southern Australia forced a rethink of how the Murray system should ration water between irrigation, the environment and towns, and the resulting reforms now include groundwater as a working part of the toolkit.

Adaptation can take simple forms. A plan might say that when dam storage falls below 30 percent, alluvial bore allocations in connected systems are halved, while deeper confined aquifer entitlements stay at full volume because they draw on a separate recharge source. Detailed seasonal water balance work, such as the Yamuna floodplain balance study, helps planners set triggers that respond to actual recharge signals rather than calendar dates.

The practical lesson is to make the triggers known to users in advance and to design the compliance pathway so that switching between regimes does not require a new licence each time.

Community engagement and indigenous water interests

Plans that ignore the people who depend on them tend to unravel when pressure rises. Conjunctive management works best where irrigators, town councils, environment groups and Traditional Owners have a chance to shape the triggers. Town meetings in places like Broken Hill during the last big dry gave engineers direct feedback on which bore should remain reserved for drinking water and which could be opened to industry under tight caps.

Aboriginal water interests have moved from consultation toward formal holding of water entitlements in several Australian basins. The Northern Territory's Aboriginal Water Reserve in the Western Davenport catchment is a useful example, where a portion of both surface and groundwater entitlements is held for cultural and economic use by Traditional Owners. On the Indian side, similar work is happening through the Jal Jeevan Mission, where village committees decide how their piped supply is rationed during the dry season and how recharge structures are maintained.

Governance frameworks that link surface and subsurface agencies

The technical work fails when institutions are split. In Australia, the Murray–Darling Basin Authority, state water agencies, local councils and catchment authorities each hold part of the puzzle, and joint programs like the Basin Plan explicitly bind them to common accounting rules. India is moving in a similar direction through state-level groundwater management plans drafted under NAQUIM and aligned with the Central Water Commission.

A workable governance model includes three elements: a shared data platform that both surface and groundwater agencies can write to and read from; a single allocation register that converts entitlements between sources; and a joint operational committee that meets during droughts and floods, not only in calm years. The longer-term shift is toward genuinely integrated water resources management, where a planner looks at the whole hydrological cycle before deciding how to allocate any share of it.

Visit the NAQUIM portal to access block-level aquifer information, recharge guidance and seasonal water balance studies that can be used to support integrated planning in your own district. The data layers are openly published and can be cross-referenced with local rainfall and extraction records to test conjunctive scenarios before the next dry spell arrives.