Dry Weather and Effects on the Tennessee River System

• The five-month period of January through May 2007 was the driest such period in 118 years. Average rainfall in the Tennessee Valley above Chattanooga has been only 11.6 inches — or 51 percent of normal.
{Jer: I wanted to clarify for you: the data are based on 5 months - not a calendar year, school year, or any other annual-like calendar.}

• TVA has been operating the river system in conservation mode since February to ensure as much water is available to fill reservoirs to recreation target levels and provide other benefits Valley citizens have come to depend on.

• Because of the dry conditions, most tributary reservoirs are significantly below their recreation target levels, typically met on June 1. On average, reservoirs in the eastern Tennessee Valley were about 10 feet below where TVA would like them to be by June 1.
{I work on the upper tributary reservoirs of the TN River system, and our stakeholders are capital-M mad that we aren't operating the reservoir levels for their selfish uses. I've suggested rain dances; I have no control over rainfall (well, only non-point and insignificant control but that is another story reserved for coffee sipping with the climate change do-gooders (wink).)}

• In 2004, TVA changed its operating policy to allow increased winter reservoir levels on most tributary projects. This change allowed more water to be in the reservoirs at the start of 2007. This, along with operating the system in conservation mode, means that although water levels are low, they are nowhere near the driest historical levels.
{Whoever writes this is clever, what a great spin on the facts!}

• At this point, it would take several sustained, soaking rains - the kind we usually only see when the Valley experiences the remnants of a summer hurricane - to raise tributary reservoirs significantly.
{Several minus one. Last night as I slept we had a hard rainstorm. I know, as my car is flooded because I left the window rolled down.}

• The long-term forecast is for continued dry conditions.

Water Quality

• TVA is providing water flows below dams to maintain water quality and protect aquatic habitat.

• These minimum flows will continue to be maintained, however, this means that more water will have to be released from the already lower-than-normal upstream reservoirs.

• Dissolved oxygen, necessary for aquatic life, is being monitored on the reservoirs throughout the river system. Due to low water flows, dissolved oxygen amounts are lower than normal on some reservoirs. TVA is examining opportunities for special dam operations that might help improve conditions on a reservoir-by-reservoir basis, but options appear very limited with so little water available.

• Prolonged continuous low flows could cause cumulative water quality impacts in mid to late summer.

There you have it - the dry grip from the rain drop. The truth is low reservoir level are also affecting TVA's ability to produce low-cost, affordable and reliable power - the hydro variety. Therefore TVA is producing more power at coal-fired and nuclear plants ($$$$). As a result it will negatively affect year end bonuses and more importantly, the budget of environmental stewardship and policy. Read: my job. What an exciting time to be working at TVA!!!