Waterwijzer Overlay

Usage

The waterwijzer overlay results can be used to:

• Calculate the loss of earnings based on existing crops for currently known highest and lowest ground water levels.
• Calculate the loss of earnings for crops when using different ground water level management strategies simulated by a Ground Water Overlay or a Subsidence Overlay.
• Determine the best type of crop per parcel given the highest and lowest ground water levels and type of soil.

Considerations

The waterwijzer overlay calculates loss of earnings for agriculture crops based on:

• A climate scenario;
• A weather station;
• Type of soil;
• Type of crop;
• Highest and lowest (averaged) ground water levels.
• The irrigation parameter, which in the Waterwijzer tool is active for a subsection of the crops, is currently not taken into account.

Result types

The overlay offers the following result types:

Result type	Unit	Description
DAMAGE_DRY	% loss of earnings	The loss of agricultural earnings for drought scenarios, for a particular crop, using the highest and lowest ground water levels adjusted by subsidence. These earnings are calculated by the Waterwijzer Landbouw api. When the water levels in the ground are too low, roots are unable to absorb enough moisture.
DAMAGE_WET	% loss of earnings	The loss of agricultural earnings due to high ground water levels, for a particular crop, using the highest and lowest ground water levels adjusted by subsidence. These earnings are calculated by the Waterwijzer Landbouw api. When the water levels in the ground are too high, subsurface air is replaced by water and plant roots cannot obtain enough oxygen.
DAMAGE_INDIRECT	% loss of earnings	The loss of agricultural earnings due to indirect causes, for a particular crop, using the highest and lowest ground water levels adjusted by subsidence. These earnings are calculated by the Waterwijzer Landbouw api. Indirect causes relate to the type of soil, type of crop and water levels. Taken into account are: soil temperatures in comparison with crop growth calendar; plowing difficulty for a soil and season; sowing problems for the given water levels, crop and soil; germination problems due to sub-optimal water concentrations in the soil; harvest issues due to not fully grown crops; sub-optimal conditions for grassland growth;
DAMAGE_SALT	% loss of earnings	The loss of agricultural earnings due to salt water irrigation or salt water seepage, for a particular crop, using the highest and lowest ground water levels adjusted by subsidence. These earnings are calculated by the Waterwijzer Landbouw api. Too much salt concentration leads to a reduction of water absorption of plant roots, increased toxicity, problems with nutrients absorption and decreased root growth.
DAMAGE_TOTAL	% loss of earnings	The total loss of agricultural earnings for a particular crop, using the highest and lowest ground water levels adjusted by subsidence. These earnings are calculated by the Waterwijzer Landbouw api.