The Importance of Water Storage in Low Snowpack Years

Pop Quiz:

Colorado’s Population is projected to increase to what number by 2060?

A)  7 million          B)  9 million     C)  11 million


Answer: C) Some projections show Colorado’s population doubling by the year 2060 to approximately 11 million people.  Source:

The Importance of Water Storage in Low Snowpack Years

As of April 27, snowpack levels statewide were 64 percent of normal, with some parts of southern Colorado as low as 20 percent of normal. Reservoir levels, however, are generally higher than usual for this time of year (see map below). This winter’s low snowpack underscores the importance of water storage in reservoirs, but many wonder if the stored water will be enough to sustain Colorado’s water needs through the summer, and longer term particularly if Colorado experiences subsequent years of low snowpack. 

Martin and Wood, along with other state water experts, has been watching levels closely and thinking ahead to the upcoming irrigation season. To help make sense of it all, we interviewed two of the State Division Engineers: Steve Witte, P.E., is the State Division Engineer for Division 2, which includes the Arkansas River Basin and its tributaries. And, David Nettles, P.E., is the State Division Engineer for Division 1, which covers the South Platte, Republican, and Laramie River basins. Here, they offer some insight and advice as we head into the warmer months:


M&W: Based on the current snowpack and reservoir levels, what do you foresee happening this coming irrigation season?

Steve Witte: “At this writing, the NRCS has pegged the SWE (Snow Water Equivalent) for the Arkansas basin at 64% of average. This drought will have its most pronounced effect in the southern half of the state. As has been noted, storage levels are high throughout the basin, meaning that municipalities have reserves on hand sufficient to meet 2018 demands. Agricultural concerns typically rely on direct flow supplies to provide the bulk of the water necessary to meet their demand and only use storage supplies to start crops and to provide their late season supply – and so will adjust acreage in an attempt to reduce their seasonal demand. Well pumping is expected to be above average.”  

David Nettles: “Northern Colorado is doing OK on snowpack, and reservoir levels are good, so we should be OK for this year. Things may get tight toward the end of the irrigation season, but if we get some timely rains we should make it through in good shape. The area south of I-70 is not in good shape. Conditions are similar to 2012. Folks in Division 1 who are dependent on South Park water will have a tight year unless we get lots more precipitation soon.”


M&W: What advice do you have for water users this summer?

Steve Witte: “There really isn't a great deal that we can offer to the agricultural community. These folks are well seasoned in adjusting to variable and often deficient water supplies. Deficit irrigation is not some type of innovative management strategy in the Arkansas basin...for farmers who have grown up here, it's a way of life. If I were to offer any advice, I would urge optimism. We've seen spring rains come following dry winters, and these can change the complexion of the entire year. The winter of 1998-99 is an example. That spring we were planning for drought right up to late April when it started to rain. Unfortunately, unlike runoff from snow pack, precipitation is very difficult to predict more than a few days in advance.”

David Nettles: “My advice would be to be careful with your water, especially in the more southern portion of Division 1, but realize we should be OK with the current reservoir levels. In other words, don't be afraid to use water, but try and save back some reservoir water to finish your crop if you have reservoir water.”


M&W: How do you think this year’s conditions compare to historic droughts in Colorado?

Steve Witte: “It is easy to compare the snowpack at this time of year from various years in the past, but the combination of storage, pumping ability and runoff from precipitation can make a significant difference. One factor looks pretty bad, two look pretty good and there's one huge unknown (precipitation).”

David Nettles: “As I said, the south of I-70 snow pack in Division 1 is very similar to 2012, but north of I-70 is better, though still below average. I expect it to be a dry year north of I-70, but not an historic drought like 2002 or 2012. Overall, I think 2018 will be remembered as a dry year in Division 1, but probably not like 2002 and 2012 are remembered.”

Reservoir Map.png

This Natural Resources Conservation Service map shows reservoir storage levels