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- More A&E
Hoping and waiting for normal
SoVaNow.com / December 05, 2012(The following letter was submitted to The Sun by Frank Timberlake, public affairs officer for Kerr Lake Park Watch (KLPW) — Ed.)
Almost historic low levels of the water in Kerr Lake are drying nerves out as well as the shorelines. The number of calls and emails is on a sharp increase to KLPW as lake users are looking for answers about Kerr Lake’s lack of water.On October 26, 2012 the US Army Corps Concern has reached an almost unprecedented level about the low level of water in Kerr Lake this season. KLPW has received a number of one-line comments and questions about the continued depletion of water in the reservoir.
Of the plea-like questions came a written request for information about the lake’s low level from Kerr Lake enthusiast and user, David Hanson, who wrote to Kerr Lake Park Watch, saying, “Please advise on how much lower you are going to release the water. I have not been able to get an answer; it is as if no one really knows. This has been the worst year that I have spent on Kerr Lake in my 19 years of being on the lake. At least tell us why and not the standard answer we are in a drought, if that is the case then start pulling water from Gaston also and not just six inches. I am assuming that our taxes will go down because we are not able to use the facilities. I am thoroughly disgusted because I have the greatest respect for the Corp with numerous friends working for the Corp.”
There are many people asking the same question, “Why is Kerr Lake so very low?” The Public Affairs Lead for Kerr Lake Park Watch went directly to the US Army Corps of Engineers to get an explanation of why the lake is so far below the guide curve this year.
Michael Womack, the Corp’s Operations Project Manager at Kerr Lake says he sympathizes with Mr. Hanson and others concerned, “as we are definitely well below normal for this time of year.” Womack offered some detailed information about the reservoir operations and conditions that have contributed to the current lake level situation:
“Kerr Lake is a multi-purpose reservoir. As such, we have target lake levels that vary seasonally to better accommodate different purposes — flood storage year-round, but especially in the winter; spawning releases in the spring; and recreation in the summer. Hydropower is a primary purpose of the project year-round and provides affordable power to communities and electric cooperatives across Virginia and North Carolina.
When rainfall is adequate, we make every effort to maintain lake levels at or near these seasonal target lake levels (also called our guide curve); however, actual rainfall (surplus or lack of) determines how well those target lake levels can be maintained. Where the lake level is (relative to this guide curve) determines how we operate the project. Generally speaking, if the lake level is above guide curve, we make controlled flood releases to bring the lake back down near guide curve to restore our flood storage. If we are below guide curve, as we have been all summer and fall due to below-normal inflows into the lake, we conserve water by reducing our energy generation to the minimum amount that we are contractually obligated to generate. This minimum generation also meets the downstream requirements for water quality. Our minimum energy commitments are highest in the summer and winter months when power customer demands are the greatest. These minimum energy amounts decreased significantly (by 33%) in October, which allowed us to conserve more water and reduce lake level drawdown. However, these minimum energy amounts increase again starting in December due to higher winter power demands.
While there was seemingly decent rainfall at Kerr Dam this summer, keeping the lake full depends on widespread rainfall across the entire Roanoke River basin upstream of Kerr to sustain inflows—but this has not been the case this year. Since April, inflows into Kerr have only been averaging about 40% of normal (based on long-term monthly median inflows), and since the beginning of July, only averaging just over 35% of normal. Since early October, rainfall has been very limited and inflows have declined even further — averaging less than a third of normal for October and ranking 8th lowest October out of 83 years of inflow data. So far for November, inflows are running less than 25% of normal and ranking 2nd lowest November). As a result of these protracted below-normal inflows, lake levels have been steadily dropping despite only generating our minimum energy amounts since the beginning of July. If you look at lakes upstream of Kerr, such as Smith Mountain and Philpott, they are experiencing low lake levels as well. We cannot predict how low lake levels will get but the goal is to raise levels back to guide curve with the help of needed rainfall in the upper watershed. Until then, we will continue to minimize the impact of the low inflows on the lake level through our operations.
While there hasn’t been an official drought designation in the NC and Virginia portions of the Roanoke Basin this summer/fall, the National Drought Monitor has persistently designated this area as “D0”, which indicates “abnormally dry” conditions. Virginia also currently has the Roanoke Basin designated as a Drought Watch area. However, if dry conditions continue, more significant drought designations are likely in the Roanoke Basin.
Seasonal outlooks indicate “equal chances” of below-normal, near-normal, and above-normal precipitation over the next few months. With near-normal (or even slightly below-normal) precipitation across the Roanoke Basin, we would begin to see some improvement in inflows and lake levels. For comparison, we’ve probably only seen about 25-50% of normal precipitation over the past 30-60 days over the basin.”
At a recent Corps meeting on the subject of Hydrilla, a Corps official, when asked about lower water levels said that an initiative several years ago that changed the guide curve to accommodate virgin Cyprus trees in eastern North Carolina had not contributed to lower levels in the lake.
It appears that it will take rain and a substantial amount of rain upstream in the upper Roanoke River Basin to help the level of Kerr Lake see normal again.