Al. Steinwand et Te. Fenton, LANDSCAPE EVOLUTION AND SHALLOW GROUNDWATER HYDROLOGY OF A TILL LANDSCAPE IN CENTRAL IOWA, Soil Science Society of America journal, 59(5), 1995, pp. 1370-1377
Deciphering the effects of land use on environmental quality requires
detailed knowledge of the processes governing soil and landscape genes
is. The objective of this study was to describe the landscape evolutio
n and shallow groundwater hydrology of a glaciated landscape in Iowa a
nd to relate the soil color pattern to water table fluctuations. Strat
igraphic and geomorphic maps and cross sections were prepared using ch
aracterization data from 128 soil cores collected from a 32-ha site. O
ne transect crossing several hillslopes was instrumented with 47 piezo
meters to determine groundwater how direction, Three strata of surfici
al sediments overlying till were identified. The upper two strata were
slope alluvium deposited after 4300 YBP, which limits the age of the
soils to the late Holocene or younger, The lower sediment resembled al
luvium and may be supraglacial sediment draped on the till and later e
roded from adjacent hillslopes. The hydrology was characterized by rec
harge under topographic highs, lateral groundwater Bow on sideslopes a
nd discharge in swales, During dry periods, however, portions of highe
r swales acted as recharge areas and groundwater flow was directed bet
ween swales. Morphologic indicators of wetness are better expressed an
d shallower in soils at footslope and toeslope positions, but some of
these features are relict because of the lowering of the water table b
y artificial drainage.