Because the carbonate aquifer in much of northwestern Ohio is the principal
water resource, understanding the avenues of recharge and resulting pathwa
ys of solute transport are crucial to the assessment of water resource avai
lability, water quality and contaminant transport. This study uses estimate
s of evapotranspiration, measurements of piezometric heads and calculations
of groundwater fluxes to investigate carbonate aquifer recharge from a sma
ll basin within the carbonate aquifer recharge area 2 km south of Whitehous
e, OH. Of the 0.240 m of soil moisture surplus, approximately 43% runs off
by way of drain tiles, ditches, and streams leaving 0.135 m as potential re
charge for the deeper carbonate aquifer, Direct recharge to the 2% of the c
arbonate aquifer that is covered by less than 2 m of overburden accounts fo
r a small percentage of the total recharge. Large amounts of radial flow fr
om this shallow bedrock area suggest contributions from sources other than
direct recharge or shallow lateral flow. The only remaining possible source
of excess recharge in the shallow bedrock area is recharge contributed by
streams through vertical fracture zones. Even where the glacial till is thi
ck and vertical permeability is low, large vertical gradients over large ar
eas induce significant bedrock recharge. Because direct recharge is derived
from soil moisture surplus and surface water contributions in the area of
shallow bedrock, the aquifer is most susceptible to contamination from thes
e sources during the wet seasons. Conversely, even though recharge through
the glacial till is maintained throughout the year, threats of contaminatio
n due to this vertical recharge are diminished.