THE MANAGEMENT OF WATER FOR 
MALARIA CONTROL 
By E. HAROLD HINMAN 
HEALTH AND SAFETY DEPARTMENT, TENNESSEE VALLEY AUTHORITY, WILSON DAM, ALABAMA 
Since the malaria-transmitting mosquito 
spends the immature stages of its life cycle 
in an aquatic environment, the proper man¬ 
agement of unremovable water affords an 
excellent prophylactic measure in the pre¬ 
vention of malaria. With the rapid in¬ 
crease of impounded water projects for 
flood-control, navigation, hydroelectric 
power development, water supply reser¬ 
voirs, irrigation, and storage, the possibility 
for increasing “man-made malaria” is con¬ 
siderable. Despite the increase of the po¬ 
tential breeding surface it is possible in 
many cases to manage water levels so that 
the environment will not be suitable for 
production of the vector; or so that the 
vector may be destroyed during the larval 
stages at intervals frequent enough to pre¬ 
vent serious production of adult mosqui¬ 
toes. To accomplish this, the future poten¬ 
tialities for mosquito propagation must be 
considered during the planning and con¬ 
struction of impounded water projects. 
Failure to do so has resulted repeatedly in 
unnecessary outbreaks of malaria. 
Impounded Water 
A quarter of a century ago the impor¬ 
tance of impounded water projects as a 
potential cause of increased malaria trans¬ 
mission was recognized in the Southern 
States. This resulted in the undertaking 
of joint studies by the U. S. Public Health 
Service and personnel of State Health De¬ 
partments. Eventually regulations were 
adopted by various State Health Depart¬ 
ments governing the impounding of water. 
In Alabama those first adopted in 1922 were 
subsequently held illegal on a technicality. 
The regulations later adopted by the Ala¬ 
bama State Board of Health (1927) have 
the force and effect of law making it im¬ 
perative that any person, firm, corporation, 
324 
county or municipality desiring to impound 
water or who propose fo raise the level of a 
previously existing pond must make formal 
application to the State Board of Health. 
Ponds of less than 1/10 acre for watering 
stock or other domestic purposes or im- 
poundages so located that no portion of 
them lies within one mile of any permanent 
human habitation are excepted. These 
regulations have served as a model for other 
states. The main objective has been to pro¬ 
vide a naturalistic or biological control of 
the malaria transmitting mosquito through 
the development and maintenance of a 
clean water surface. This has been sought 
through: (1) proper reservoir preparation, 
(2) water level fluctuation, and (3) shore¬ 
line maintenance. The. management of 
water level alone does not prevent the 
propagation of mosquitoes, for in the final 
analysis the control of mosquito breeding 
depends upon the control of vegetation, 
hence it is necessary to maintain a biologi¬ 
cal imbalance. 
Reservoir Preparation 
Smillie (1927) reported studies of an epi¬ 
demic of malaria at the Gantt impounded 
area in Southern Alabama in an area of 
mild malaria endemicity. Impoundage in 
violation of regulations after only partial 
clearing of the reservoir resulted in a severe 
epidemic of malaria, beginning July 1 and 
extending to the middle of November, 1924. 
(This epidemic was only one of a series 
resulting from inadequate clearing of reser¬ 
voirs prior to impounding.) 
The principal requirements in reservoir 
preparation have been summarized by 
Kiker and Stromquist (1939) as follows: 
“That the reservoir be cleared so as to pre¬ 
sent a clean water’s surface after impound¬ 
age between maximum and minimum water 
