Storage & Reservoir Management to Cut Evaporation

What it is

Storage and reservoir management reduces evaporation not by covering the water but by changing the shape, depth or location of the storage itself. It is a different engineering class from the surface methods elsewhere on this site — these are capital works and operating strategies rather than products laid on the water. Common approaches include reservoir deepening, compartmentalisation, and moving water into underground or aquifer storage.

How it works

The physics points straight at one variable. As explained in what is evaporation, depth does not change the evaporation rate per unit area — but surface area sets how much water is exposed and therefore scales total loss. Storage management works by shrinking, consolidating, or eliminating that exposed surface.

• Deepening. Storing the same volume in a deeper, smaller-footprint basin exposes less surface area per unit of water, so total evaporation falls even though the local rate is unchanged.
• Compartmentalisation. Dividing a large reservoir into cells and concentrating water into fewer, fuller compartments as levels drop keeps the exposed area smaller than letting a single shallow pool spread out.
• Underground / aquifer storage. Recharging water into an aquifer or holding it in covered/buried storage removes the open surface almost entirely, eliminating surface evaporation rather than just reducing it.

How well it works

The benefit is indirect — it reduces exposed surface area or shifts storage out of the open air — so it is best expressed as a strategy rather than a single suppression percentage. The actual saving depends entirely on the geometry change or the volume moved underground, which is why this site frames it qualitatively. Craig et al. (2005) discuss these structural and operational measures alongside covers as part of a complete evaporation-control toolkit.

Trade-offs

• Capital and feasibility. Deepening, building compartments, or developing aquifer storage are major works with high cost and long timelines, and feasibility is highly site-specific.
• Complexity. Compartment management adds operational decisions; aquifer storage depends on suitable geology and on protecting water quality during storage and recovery.

Where it fits

These measures make most sense when building or upgrading storage, at utility or large agricultural and industrial scale, or where surface covers are impractical across a very large area. They also combine well with surface methods — for example pairing compartment management or a geomembrane on a smaller, deeper basin, or adding windbreaks. Where a surface barrier is the better fit, compare geomembrane covers and the full methods comparison.