No - Blithfield was always intended as a drinking water reservoir, and was planned before 1939. It was formed by building a dam to block the river Blith. Its history is here:
http://www.blithfieldeducationcentre.co.uk/reservoir.htm
You may be thinking of the explosion at RAF Fauld in 1944, when an underground munitions dump exploded with the loss of about 75 lives:
http://en.wikipedia.org/wiki/RAF_Fauld_Explosion
Died: 12 August 1944 (wartime plane explosion)Source: Answers.comDied: 12 August 1944 (wartime plane explosion)Source: Answers.comDied: 12 August 1944 (wartime plane explosion)Source: Answers.comDied: 12 August 1944 (wartime plane explosion)Source: Answers.comDied: 12 August 1944 (wartime plane explosion)Source: Answers.comDied: 12 August 1944 (wartime plane explosion)Source: Answers.com
Winter in Wartime was created in 1972.
Wartime Nutrition was created in 1943.
During Wartime was created in 1988.
Wartime Lies was created in 1991.
Wartime Romance was created in 1983.
Wartime Wedding was created in 1974.
Wartime - Doctor Who - was created in 1987.
The duration of Wartime Romance is 1.53 hours.
Wartime and post-wartime paranoia.
The duration of Wartime Nutrition is 600.0 seconds.
Wartime Information Board was created in 1942.