Highlights:
- March precipitation is above normal in just about every location in Delaware, especially Sussex County.
- Stream conditions in northern Delaware are improving, and chloride levels on the Christina are decreasing.
- Groundwater conditions are below normal at most wells in the state, but they have continued to improve due to the wet March conditions.
- Long-term (Spring 2025) drought outlook shows drought conditions improving statewide.
Statewide Drought Discussion
March 2025 precipitation finished on a high note on Monday night. For the month, nearly every location in Delaware ended up with above normal precipitation. In fact, many locations in Sussex County saw 1.5 to 2.0 inches more precipitation than normal in March. Figure 1 shows precipitation measured by the DEOS network between March 1st and March 31st.
Looking at stream conditions, the flow on White Clay Creek at Newark and the combined flow of the Red Clay Creek near Stanton and the White Clay Creek near Newark (combined flow at Veolia’s filter plant) slightly increased when compared to last week. However, as of Tuesday morning, the full impact of the rain that fell throughout the region on Monday night is not yet showing up in the streams. The flows on the Brandywine Creek have increased almost 6 mgd since March 24th, and are closer to what they were at the beginning of March (Table 1). Although the streams in New Castle County are doing well as far as not being in drought status, unless there is additional precipitation, within a week they will most likely be flowing below their respective medians for this time of year.
Chloride concentrations in the Christina River near Newport remain well below the first threshold of concern (250 ppm) at 47 ppm. The last time the chloride concentration was above 250 ppm was during the first week of March (263.2 ppm). In general, chloride conditions have improved throughout the month as precipitation conditions have improved.
Groundwater conditions continue to improve statewide. The water level in well Db24-18 (located just south of Newark) has increased to 15.0 ft below land surface (Table 1). It is slowly starting to recharge, and hopefully will be out of drought warning status soon. The water level in this well typically ranges between 9.7 and 13.3 ft below land surface during April. Well levels are recovering in southern portions of the state, also. Pf24-02 (south of Georgetown, near Stockley) has recovered above the median for this time of year (Figure 2). Mc51-01a is still well below the median for this time of year, but has shown enough improvement to exceed where it was during the 2001-2002 drought – the last major drought to affect all of Delaware and the Mid-Atlantic region (Figure 3).
Weather and Climate Outlook:
As we move into the first week of April, we should continue to see some precipitation. The latest forecast model guidance isn’t showing the 1-2 inch events we’ve seen over the last 10 days, though. Some locations could see more, but generally 0.50-1.00 inches of rain is expected between now and April 8th. That’s not a lot, but we’ll take it, and it should be enough to offset expected evapotranspiration over the same time period. As we get later into April, evapotranspiration will play a more significant role in our drought conditions as the natural environment “leafs” out.
The drought outlook (Figure 4) is showing some modest improvement, possibly even the ending of drought in Kent and Sussex counties later this spring. Meanwhile, drought conditions should improve but may persist from New Castle County into southeast Pennsylvania, where the headwaters for some of our water supply streams and creeks are located.
