Drought in Delaware

Note:  The next drought report will be on July 15th, 2026

Highlights:

• May 2026 was the 10th straight month with below normal, statewide precipitation.  
• The 10 month period from August 2025 to May 2026 is the driest August to May on record for Delaware going back to 1895-1896.  
• Streamflows at numerous stream gauges across the state are considerably below normal, with some locations experiencing their lowest levels ever for this time of year.
• Well levels continue to decline as result of the long-term, below normal precipitation conditions
• The short-to-medium term outlook looks somewhat promising, with above normal precipitation predicted for the northeastern region of the U.S. between the last week of June and the first couple of weeks in July.

Statewide Drought Discussion

Precipitation

July 2025 was Delaware’s last month with above normal precipitation.  Since last August, every month has been below normal (see Figure 1), resulting in a precipitation deficit of 14.89 inches over that timeframe.  

Looking at June rainfall totals from the DEOS Network, the first half of June has been significant in the north, especially north of Middletown and in the Rehoboth Beach area, and pretty dismal elsewhere, particularly in most of Kent County (Figure 2).   More significant rain is needed during the rest of the month in order to finally put an end to our dry month streak. 

Temperature/Evapotranspiration

Delaware has experienced above normal temperatures for most of May and June.  Correspondingly, relatively high evapotranspiration rates have been experienced across most of the state over the last 30 days, according to data from the Delaware Water Tracker (Figure 3).  This continues a trend that has existed throughout the spring, and only compounds the worsening of drought conditions, as more water escapes from vegetation and the land surface.  June and July tend to be the peak months for reference evapotranspiration for Delaware.  This will make improving our drought conditions even more difficult without significantly more rainfall than we’ve been seeing lately.    

Soil Moisture

Soil moisture varies significantly depending on where you live in Delaware (Figure 4).  While northern New Castle County is enjoying near normal soil moisture for this time of year, all of Kent County and most of Sussex County are at or below the 5th percentile.  With soil moisture this low, many farmers and homeowners are running their irrigation systems daily or even multiple times a day right now.  While there are no known widespread water supply issues at the moment, the combination of increased irrigation pumping (where groundwater and surface water is the resource) and limited precipitation to replenish soil moisture is increasing pressure on our aquifers, creeks, lakes, and ponds.  

Streamflow

The sustained three-month decline in Delaware’s streams is not just a seasonal fluctuation; it is a clear hydrological anomaly. Spring is typically the peak recharge period for streams in the Mid-Atlantic, which is driven by winter snowmelt and a peak in precipitation relative to other parts of the year. Added to the lack of precipitation is the fact that the streams did not fully recover from the low flows that occurred in the fall of 2025. When streamflow drops steadily over a three-month spring window, the resulting shallow depths and reduced water velocities can lead to elevated water temperatures and physical obstacles, which could impact the local fish habitat.

In northern New Castle County, by mid-spring, the flows on White Clay Creek, Red Clay Creek, and Brandywine Creek at Wilmington dropped into the bottom 5th to 10th percentile range. This means that for this specific time of year, the flows are “much below normal” and are encountered less than 10% of the time in our recorded history.

In Kent County, the St. Jones River at Dover has maintained flow in the below normal  range (10th – 25th percentile) with a few exceptions in the normal range. However, the Nanticoke River at Bridgeville dropped into the critical  (i.e., below the <5th percentile) tier during the winter and early spring before marginally recovering to the 5th-to-10th percentile. Normal flows for all streams in the state should be between the 25th and 75th percentiles.

These sustained low-flow conditions pose significant risks to aquifer recharge and water quality parameters. To transition these systems back to seasonal norms, the state needs a sustained period of significant, above-normal precipitation over the next 60 days to offset current deficits.

Chlorides

One of the most definitive indicators of a regional drought is the behavior of the Delaware River salt front—the interface where salty ocean water meets fresh river water; however, the specific conductance (a proxy for chloride) readings at the Christina River at Newport have remained quite low since March. The most recent reading resulted in a calculated chloride concentration of approximately 48 parts per million, which is much lower than the secondary maximum contamination level of 250 ppm.

This should not be taken as a sign that hydrologic conditions aren’t serious. Even though the flows on the tributaries are very low, the water at the gage at Newport is being kept fresh by a continuous flow of freshwater coming down the mainstem Delaware River.

Groundwater

Streamflow is tied to the water table, and like streams, spring is the time of year that the shallow, unconfined aquifer should be recharging. Near Newark, this aquifer as measured in well Db24-18, dropped to over 14.5 feet below the land surface (fbls), which exceeds the typical spring average of 8 to 12.7 fbls.  A substantial amount of precipitation will be necessary for the water level in this well to recharge 1.8 ft, which will only bring this water level to the very low end of normal for this time of year.  A critical USGS/DGS monitoring well in southwestern Kent County (Mc51-01a) has consistently been tracking below the 5th percentile, which has the potential to be a record low for this well. In May, the normal water level in this well is between 10.3 and 12.7 fbls; however, the current water level is at 15.5 fbls, which is extremely below normal (Figure 5).

At least one well (Pf24-02 located south of Georgetown) remained within the normal range, reflecting geographic variability in groundwater response across Delaware.

Delaware’s groundwater system responds slowly to changes in precipitation compared with surface waters (like streams and rivers). As a result, patterns of dry weather tend to show up first in streamflow and soil moisture, and then, if dry conditions persist, in groundwater levels and aquifer conditions.

Groundwater is a major source of drinking water and irrigation supply in much of Delaware, especially south of the Chesapeake and Delaware Canal. Extended periods of low levels can reduce well yields and may require deeper pumping or alternative supply strategies in some communities. Persistently low groundwater levels increase the risk of saltwater intrusion in coastal and near-estuarine aquifers, complicating long-term freshwater sustainment. In addition, low groundwater can stress wetlands and baseflow conditions to streams during dry periods, affecting fish, invertebrates, and riparian habitats.

Weather and Climate Outlook

Precipitation opportunities will be limited through early next week, however, there is some hope in the NOAA Climate Prediction Center’s (CPC’s) short-to-medium outlook.  A more active weather pattern is expected in the 8-14 day outlook, which covers the final week of June (Figure 6).  This could mean above normal precipitation (i.e., more than ~1.05 inches) over this timeframe.   

The CPC Week 3 through 4 outlook also shows a slightly above normal probability of above normal precipitation for the northeast region of the United States in the first couple of weeks of July (Figure 7). 

Hopefully we see above normal precipitation come true, since the average reference ET is around 3.5 inches during the same timeframe as the two CPC outlooks.  While 3 to 4 inches of rain wouldn’t come close to ending our drought, it would likely eliminate the chance of worsening the current drought.