Groundwater Levels

Marlborough District Council monitors the state of the region's aquifers based on water levels in its network of 30 wells spread across the district.

To check out the relative state of the aquifer you are interested in, select a black point on the map, or a site from the lists below. These are linked to graphs that show the variation in groundwater level at the Council monitoring site, over what we call a 'water year' from July to July. The blue line represents the level since last July in metres above mean sea-level. The grey line shows what happened a year ago.

The different coloured shading indicates how the current level compares with historic levels. For example, the lower green zone shows the lowest 20% of values observed and when the blue worm is in this region, levels are relatively low. The light green line running through the centre of plot is the average.

Conversely, when levels lie in the upper green zone, the aquifer is full and well levels in the area it represents are likely to be high.

The middle yellow zone containing the remaining 60% of observations is where the level will sit most of the time and is termed normal.

The shape of each plot at each monitoring site varies depending on local factors such as pumping and the recharge mechanism. Most sites peak in winter or spring and reach their lowest level in late summer.

Some sites have a long period of record and we can be more confident about the relative status of aquifer levels because they include extreme values. The date records started from is given for each site. The earlier records start, the more representative the plot, because it includes extremes such as droughts.