The latest Water New Mexico Water Supply Outlook Report is now available.
From the Summary: “Statewide increases in both Snow Water Equivalent [SWE] and total precipitation during February continue to paint an optimistic water supply picture for New Mexico’s major river basins. Above to well above normal streamflow volumes are now likely for the runoff period in every aggregated basin system aside from the Canadian which has not seen the same magnitude of precipitation as other regions since the start of the 2023 water year. Most significant February gains in SWE were seen in the western New Mexico’s San Juan, Zuni, Gila-San Francisco, and Lower Rio Grande basins, as well as in the upper Pecos. This new snowfall has the potential to substantially improve the outlook for snowmelt translating into observed streamflow during the spring runoff period when compared to calculations produced last month. When compared against March 2022 observations, the snowpack and overall water supply picture are greatly improved. Generally robust fall baseflows coupled with reduced soil moisture deficits going into winter should combine with these improved snow totals to translate into higher runoff efficiencies than those of recent years. Many factors influencing how the melt season unfolds (such as dust on snow events as seen in widespread areas across the southwest last year, or early rainfall occurrence) may have a substantial impact on spring and summer runoff cycles. With the last month of precipitation accounted for, New Mexico’s basins generally show much higher likelihood for near to above normal runoff as compared to the outlook for February. Streamflow forecasts generally reflect this trend.
A cool and generally wet month across much of the Rio Grande has been very good for snowpack accumulation in this region’s mountains and the water supply forecasts have moved up from February calculations accordingly. While much of the basin appears poised to reach at least median volumetric runoff outcomes, the Saguache and Sangre de Cristo Mountain basins north of Taos will likely need above normal precipitation for the remainder of the snow accumulation period to reach that threshold. In the Canadian basin, forecasts jumped on the Cimarron and Rayado Rivers, where headwaters received much above normal precipitation. Confidence is increasing for above median flows in many forecast basins for the runoff period. February precipitation was again above median across much of the San Juan and lower Colorado contributing basins west of the Continental Divide, and the snowpack is currently far above normal peak levels in these portions of New Mexico. The water supply forecasts for western New Mexico reflect these conditions, and all forecast points along the New Mexico- Arizona state line are expected to see streamflow exceed median volumes by a considerable margin.
Forecast skill will continue to improve as more of the winter season weather has been recorded, so the range of possible flows throughout New Mexico’s forecasted basins can be expected to narrow as peak SWE is reached and snowmelt begins. March and April are critical months for determining what the fate of the snow that has already fallen will be as well as how much additional moisture may be added to the existing snowpack.”
- Jaz Ammon, Water Supply Specialist (Hydrologic Technician)