News - Drought Impact (23 September 2002)
Mandatory water restrictions are in place in most of the Commonwealth due to Executive Order #33. Only southwest Virginia, parts of northern Virginia and the Eastern Shore are not included in the order.
Reservoir and stream levels that support public water supplies have improved slightly since late August. The town of Orange is anticipating a water shortage emergency within two weeks. The town has made emergency plans to pipe water about 20 miles from a location near Culpeper using a surface laid pipeline.
The Albemarle/Charlottesville and Portsmouth public water supply reservoirs are approaching 50 percent capacity.
Ground water-based public water supplies in Amherst, Appomattox, Augusta, Botetourt, Caroline, Clarke, Fluvanna, Fauquier, Loudoun, Nottoway, Shenandoah and Warren counties have reported dropping ground water levels or reduced yields.
Streamflows in the Shenandoah, Potomac, James and Roanoke River Basins are generally below the normal range of flow observed during September but above monthly minimum levels.
Streamflows in the Chowan, Kanawha, Big Sandy and Tennessee River Basin are in the normal range of flow. However, the low levels of ground water storage will speed the decline in these streamflows without additional precipitation.
Ground water levels continue to decline. Levels of large reservoirs such as Smith Mountain Lake, Kerr Reservoir and Philpott Reservoir continue to decline despite variances to required minimum discharges. Lake Moomaw is currently operating under a reduced release that is supplying less than one half of the flow measured in the James River near Richmond. Streamflows over the majority of the Commonwealth are well below levels expected in August. Record minimum flows for the period are expected at streamgauges in the Shenandoah, Rappahannock, York, James and Chowan River basins.
Virginia Department of Health issued over 2,900 private well replacement permits for private water supply wells that have failed since July 1. Average water conservation savings at large public water supplies of six to 12 percent have been reported since the implementation of the Governor's Executive Order #33 on Aug. 30.
The Department of Environmental Quality met with large users on the Roanoke River on Sept. 19 to begin discussions regarding allocating the limited flow in this river.
Scattered rainfall during the last month did little to improve the agricultural conditions across the state. Without significant sustained rainfall soon, the agricultural situation in Virginia will continue to deteriorate creating major problems for farmers over most of the state. The lack of subsoil moisture may prevent the planting of many fall crops.
The number of federal drought disaster designation requests submitted to Gov. Mark Warner more than doubled between August and September, from 30 to 73. The requests come from 60 separate counties, with 13 submitting a second request for additional damages experienced since their original submissions.
The U.S. Secretary of Agriculture has approved primary disaster designation for 10 of the localities (Bedford, Brunswick, Buckingham, Cumberland, Fluvanna, Goochland, Louisa, Orange, Prince Edward and Rockbridge counties) and denied disaster designation for six localities (Augusta, Bland, Nelson, Page, Rockingham and Wythe counties) whose loss of production did not meet the 30% federal requirement.
Thirty-eight contiguous counties were also approved for federal assistance and eight localities that received primary designation have also received secondary designation.
The Governor has requested federal designation for 40 other localities whose approval is still pending. Damage assessment reports (DAR) are pending from USDA for 17 localities (Albemarle, Alleghany, Amelia, Amherst, Campbell (2nd request), Charlotte, Chesterfield, Culpeper, Dinwiddie, Essex, Fauquier, Isle of Wight, Louisa (2nd request) Prince George, Pulaski, Scott and Warren counties).
Light rainfall during September has helped to minimize short-term wildfire activity across the state. In spite of the much-needed rain, drought indices remain higher than normal throughout the Commonwealth and statewide conditions are again favorable for increased and extended wildfire activity.
The Department of Forestry has cancelled all prescribed burning projects in support of the Governor's executive order and is urging other concerns to follow suit.
Due to significant drops in stream and lake levels throughout most of the state, access at boat ramps and fishing piers is increasingly limited and recreational opportunities are reduced. Of the Department of Game and Inland Fisheries' 225 public boat access sites, 131 still support normal launching, 71 report low water but may be used, 19 report no water on ramp but hand launching of small boats is possible and four are closed for repairs.
There has been some increased fish mortality at one Department of Game and Inland Fisheries' trout hatchery and fish stress levels have increased at all hatcheries. Flows at trout rearing facilities have decreased by 20 to 40 percent in the past eight weeks. Though there have been no drought-related fish kills reported in public waters, private pond owners have reported very low levels and some ponds have dried up resulting in loss of fish.
The Virginia Drought Monitoring Task Force's complete report can be found on this site or at the Virginia State Climatology Office Web site at http://climate.virginia.edu/
September 23, 2002
Precipitation for the last 30 days was above normal in Tidewater and the southeastern Piedmont, in the normal range for the remainder of the Piedmont west approximately to Route 29, and substantially below normal for most areas further west — the greatest departures from normal occurred in the central Shenandoah Valley.
As a result, near-term moisture conditions have improved in southeastern Virginia, roughly eastward of a line from Westmoreland County, through Richmond, and along I-85 to the North Carolina border.
Conditions in the zone of normal rain, from west of that line roughly to Route 29, experienced a slight deterioration. This is because normal rainfall at this time of the year is less than the normal amount of evaporation that can occur from a wet surface. As a result, regions subjected to the pre-existing major drought show little, if any, improvement with normal summer rainfall. The potential also exists for isolated pockets within these larger regions to experience much greater stress while we remain in the seasonal regime of scattered thunderstorms.
West of Route 29, and especially in the Shenandoah Valley, rainfall was below normal, with portions of Rockbridge, Augusta and mainly southern Rockingham County receiving less than 25% of long-term average rain for the last 30 days.
Attached is a table detailing precipitation departures from normal for Virginia’s six climatological divisions for selected periods back three years, the time frame of the current drought regime. A series of charts plot the progression of drought for each division. These are the cumulative percentages of normal rainfall going back to January 1999. These call stark attention to the persistent and severe nature of the drought in the Central Mountain/Shenandoah region.
The most noteworthy aspect of this updated table is the very low figure (42% of normal rain) for the Central Mountain (Shenandoah) Climatological Division since August 1. The near-term recovery on the Eastern Piedmont is also evident in this same period; note that there is roughly a west-to-east gradient in rain within this region.
Much of the above normal rain in southeastern Virginia resulted from moisture from the remnants of Tropical Storm Hanna on September 14-16. The amount of tropical cloudiness has increased some in recent days, although the intensity of activity (despite a normal number of named storms) remains far below normal for this time of the year. It is noteworthy that last year’s hurricane season, which was the second consecutive year in which there was no landfalling hurricane on the Atlantic/Gulf Coast, was also characterized by a very late beginning. The lack of a landfalling hurricane for a third consecutive year would be a record event in the 132 years of the modern hurricane record.
Streamflows are normally near their seasonal lows at this time of the year. Consequently, the setting of a daily low record could well be the lowest absolute streamflow ever observed in some regions. Many gauged and unmonitored locations in northwestern Virginia, especially in the Shenandoah, Rapidan and Rappahannock River systems, continue to set daily lows.
Within the next month, seasonal evaporation rates will drop to below half of the peak values observed in the summer. Consequently, even slightly below normal rainfall should result in some near-term amelioration in the driest regions. However, it is noteworthy that, in the current regime, fall months have been among the driest.
There is no known dynamic explanation for the persistence of what is a rather circumscribed but clearly severe drought in the Mid-Atlantic. However, one of the mechanisms responsible—a lack of landfalling hurricanes—predisposes the region to accentuated shortfalls in September and October.
As of this writing, there is no strong evidence that the climatological regime responsible for our prolonged drought is about to end. Weak El Niño conditions in the tropical Pacific only show a statistically significant correlation with lower-than-normal hurricane activity, and show no significant correlation with winter rainfall in Virginia. This is true here despite a demonstrable relationship between El Niño and winter rain elsewhere in the nation.
However, very strong El Niño conditions are associated with an increased frequency of winter coastal storms. If this particular El Niño became much stronger than anticipated, it might break the current regime. All interests should therefore watch the progress of this event as it evolves in the tropical Pacific.
http://climate.virginia.edu/advisory/advisory.htm September 23, 2002
