Water Supply

Maintaining an adequate water supply remains challenging amid changing demands, climate, and supply reliability.  Sound planning needs to consider both the hydrology of the system (that which nature controls — basin size, amount of rainfall, etc.) and the operation of the system (that which humans control — when and how much water to release from a reservoir, when and how much water to divert to irrigators, and so on). The old adage, "An ounce of prevention is worth a pound of cure," certainly applies to the management of water supply systems. Sound planning now can prevent years of havoc.

Drought management and capacity planning are inseparable, so we work closely with water suppliers to address both aspects using our OASIS software.    

Drought Management

Relating drought indicators to drought impacts is challenging -- it depends on the type of drought, the impacted user, and the source of supply.  The Drought Monitor provides an indication of drought severity, but impacts to water suppliers are system-specific.  For example, having a reservoir instead of a run-of-river supply can change drought risk significantly. 

HydroLogics creates operating rules with quantitative triggers that take the guesswork out of managing drought conditions. A trigger is a threshold probability of a critical state (such as groundwater, reservoir, or streamflow levels) at a forecasted time in the future. Using forecasts of inflows, recent watershed conditions and projected demands, OASIS can advise when to invoke conservation measures. Timely response – without false alerts – allows managers to avoid water restrictions that are not needed, while insuring that measures are taken soon enough to be effective. 

Capacity Planning

Traditionally, capacity planning has revolved around the concept of “safe yield,” which assumes that if demand is less than the safe yield, the system is reliable. HydroLogics believes that safe yield is a poor measure of reliability since managers would never operate to the safe yield in a major drought for fear of running out of water. 


Our approach considers risk explicitly. We help develop plans that reduce demands progressively and call on backup supplies as a drought intensifies. Our solutions allow managers to create more reliable and robust operating policies, often saving considerable capital and operating costs.  This approach underlies our Taking the Doubt Out of Drought campaign that has resonated with water suppliers both large and small.


For a utility case study highlighting the risk management approach, click on our forecasting flyer below. 



For an overview of our risk management approach,

view our American Water Works Association publication below.  



For an animated presentation of the advantages of forecasts over more traditional drought plan triggers, view the Prezi below by clicking on the "Forecasting" title hyperlink. 
For iOS users, go directly to this link:



For an animated overview of our risk management approach and projects where it has been applied, click below. 

"You saved us $70 million and our customers love it. Plus we have much more confidence in managing our system. Your forecasts in the last drought were right on."

Paul Blount, former Director of Water Resources, Rocky Mount, North Carolina

© 2016 by HydroLogics