Groundwater Contour Mapping

visualisation

Water table contours, flow direction and hydraulic gradient from well levels.

Data

One well per line. Columns can be separated by spaces, commas, semicolons or tabs, so you can paste straight from Excel.

Column	What it is	Example
1. X	Easting, or longitude	150
2. Y	Northing, or latitude	100
3. Level	Groundwater level, not depth to water	9.62
4. Name(optional)	Well name, drawn on the map	MW05

A line looks like 150 100 9.62 MW05

Where you have top-of-casing height and depth to water, enter the resulting level (casing height minus depth to water), not the two parts.

Drop a CSV or Excel file here, or

Read in your browser and put in the box below. The file itself is not uploaded.

15 well(s) parsed

Options

Vertical datum

Contour interval (m)Grid resolutionIDW power (residuals)InterpolationSmoothed passes near each well level; exact passes through every one, which puts a closed contour around each well. Limit to data extent Limit the contours to the area the wells cover, rather than extrapolating past the network. Show flow direction arrows Drawn from the fitted gradient. Turn them off where the gradient is too shallow for the direction to be worth stating. Downloads follow this setting.

Paste your well levels and run the analysis

A contour map with flow direction will appear here.

What this calculates

Contours a groundwater surface from well levels at a selectable interval, with flow direction arrows and the hydraulic gradient. The surface is a plane of best fit through the well levels plus inverse-distance-weighted interpolation of the residuals - this captures the regional gradient exactly (plain IDW alone would flatten it towards the mean) while still showing local detail such as mounding or a pumping depression. Supports surveyed levels reduced to a datum (mAHD) or an arbitrary local datum (relative only).

Method references

The hydraulic gradient and flow direction are the multi-well generalisation of the classic three-point problem in hydrogeology.