Drought Impacts on Maryland 
and Chesapeake Bay

Current Drought Status Drought in Maryland Impacts on Plants 
and Animals
How Drought Affects the Chesapeake Bay
Salinity in the Bay ranges from near zero parts per thousand (ppt) in the tidal fresh areas of the upper Bay to as much as 26 ppt in the vicinity of station CB5.3, east of Smith Point near the Maryland and Virginia state line.  Seasonal and long-term changes in salinity are the result of variations in the amount of fresh water flowing into the Bay. The past several years have generally been marked by lower precipitation, and consequently reduced freshwater inflow to the Bay and higher salinities (See the River Input Monitoring Program web page for a comparison of flows.) click on a station to view the surface and bottom salinity data

Click on a Station name to see the data

Freshwater flow from the Susquehanna River, which contributes approximately 60% of the total flow to the Bay, was below the long-term (1985-2000) average for all of 2001 and eight months in 2002.  As the station charts demonstrate, salinities for several main Bay stations have been higher than the long-term average (1985-2000).

Salinities in 2001 through September 2002 at most tributary stations (see the Current Conditions Web Site) exceeded their respective long-term averages. This is particularly evident at the Ragged Point (LE2.2) and the Severn River (WT7.1) stations. Due to low rainfall in 2001 and most of 2002, the salinities in 2002 were quite high in the tributaries and main Bay compared to the last 17 years. See real time salinity data at Maryland's continuous monitoring stations.

Salinity at the main Bay station near Gunpowder Neck is most likely to be affected by flow from the Susquehanna, given its proximity to the river mouth. (Salinity at main Bay stations above Gunpowder Neck is negligible). Surface salinity in 2001 was above the long-term average for the entire year, with a new maximum occurring for the month of November. Surface salinity at CB3.1 for January - April 2002 is even higher than January - April of 2001. The salinity in February 2002 exceeds the 1985-2000 average for the month of February by 280%. April surface salinity is approximately 4 times higher than the long-term April average; however, following rain in May and June, surface salinity dropped to slightly below the long-term average (May) and near the long-term minimum for the month of June.  Low rainfall in July and August resulted in above average salinity values for those months and the salinity in September is over 2 ppt above the long-term maximum.  Salinity in October dropped considerably following above average rainfall; however, it was above the average for that month.  Salinities in November and December were appropriately1 and 2 ppt below their respective monthly averages.  Bottom salinity at CB3.1 is more variable than the surface salinity and only seven months in 2001 exceeded the long-term average. Record high salinities were observed during the months of March, April, and November of 2001. Salinities in 2002 ranged from average (January) to over 4 ppt above average (May).  Salinity in August was 1 ppt above average and salinity in September was slightly above the long-term maximum.  Despite above average rainfall in the last three months of the year, bottom salinity was largely unaffected and remained near long-term maximum values.

a graph of Gunpowder Neck bottom salinity

a graph of Gunpowder Neck bottom salinity

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Surface salinity at CB3.3C (near the Chesapeake Bay Bridge) for 2001 was above the long-term average for all months except April and September (a record high for February was observed in 2001).  Salinities continued to be well above the long-term average in January - April 2002.  April 2002 surface salinity slightly exceeded the maximum value observed during the 1985-2000 period.  Following rain in May, salinity dropped to long-term average levels.  Additional rain in June resulted in a salinity of 5.2 ppt, roughly 2.5 ppt below the long-term average.  A drier July and August resulted in salinity values of approximately 2 ppt and 3 ppt above average, respectively.  Salinity in September was 2 ppt above the long-term maximum.  Salinity during the last three months of the year trended downward from the September peak following three months of above average rainfall, but still remained above the respective monthly averages. Bottom salinity at the Bay Bridge was above the long-term average for most of 2001 and for January - November 2002. New monthly maximum values were observed in April, June and December 2001 and in January and July of 2002.  December 2002 salinity was slightly below average.

a graph of Bay Bridge surface salinity

a graph of Bay Bridge bottom salinity

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Surface salinity at CB4.2C, a mid-channel station located southwest of Tilghman Island, was above the long-term average for all of 2001 and January - May of 2002.  Salinity in June 2002 dropped to slightly below the long-term average following rain early in the month; however, below average rainfall in July and August resulted in above average salinities for those months, with August nearly reaching the long-term maximum.  Salinity in February, September, October and November exceeded the long-term maximums for those months.  Despite three months of above average rainfall the December 2002 salinity exceeded the long-term mean.  New maximum values in bottom salinity were observed in the months of January and December of 2001, and April 2002.  Bottom salinity was well above average for 2002 through July; however, August salinity is only slightly above average. September salinity is well above average and nearly equals the long-term maximum.  Salinity trended downward from the September peak following three months of above average rainfall and reached the long-term average in December.

a graph of Tilghman Island surface salinity

a graph of Tilghman Island bottom salinity

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Although the influence of flow from the Susquehanna River is waning by CB5.2, a mid-channel station east of Point No Point, surface salinities in 2001 at the station were still above the long-term average because flow at all major tributaries was low. Surface salinities for January - May of 2002 are well above historic ranges. Following rain in June, salinity decreased considerably, but remained slightly above average.  Mean monthly salinity values trended upward through the summer, establishing new maximum values for August, September, and October.  Above average rainfall during the last three months of the year did not greatly affect salinity.  Bottom salinity exceeded the long-term average from September 2001 through November 2002.  Long-term monthly maximum values were exceeded in April, June and October of 2002.  Salinity declined in September and October following above average rainfall and reached the long-term average in December.

a graph of Point No Point surface salinity

a graph of Point No Point bottom salinity

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Surface salinity in 2001 at CB5.3, which is located east of Smith Point in the mid-channel at the Maryland and Virginia state line, was above the long-term average for the entire year, with a new maximum observed in December. The February through May and July through October 2002 salinities have set new record highs for each month.  October salinity is even greater than that of September, despite the above average rainfall for that month.  Although salinity dropped in November, it still remains above average. December salinity is only slightly below the long-term maximum.  Bottom salinities for CB5.3 have exceeded the long-term average since November 2001, with March, April, June and September 2002 setting new record highs.  Salinity gradually decreased during the last three months of the year following above average rainfall and reached the long-term average in December.

a graph of Smith Point surface salinity

a graph of Smith Point bottom salinity

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