Water Technology and Sciences - November - December, 2014 - page 164

162
Hernández
et al.
,
Joint Water Management in the Tambula-Picachos Sub-basin, Guanajuato, Mexico
Water
Technology and Sciences.
Vol. V, No. 6, November-December, 2014
was estimated, which has decreased over
the past 20 years possibly due to the effect
of climate change.
As analternativemethodfor comparison
purposes, direct runoff was evaluated
using a method to transfer hydrometric
information by extracting information from
La Begoña (I and II) hydrometric stations
located in a basin 18 km northeast of San
Miguel deAllende, with an area of 408 km
2
.
La Begoña station takes measurements of
the Upper Laja River Basin (4,984 km
2
) and
the Cinco Señores stations.
The Temez (Témez, 1977) model was
used to simultaneously calculate direct
runoff and potential recharge, using as
a reference weighted mean precipitation
and temperature data recorded at the five
weather stations in the study area and the
compilation of qualitative information to
corroborate and validate the surface runoff
data in the study area. Infiltration was
calculated only for UE-1 since this is the
only zone that affects the recharge of the
SMA aquifer.
A storage volume between 7.08 and
8.85 Hm
3
/year was estimated for the sub-
basin. This was estimated according to the
surface area (3.54 km
2
) of the water bodies
identifiedbythe“LandandVegetationUse”
map from 1993 and 2003 and considering a
gross average depth of 2.0 to 2.5 m for the
dikes and dams in the study area. A stored
volume in the sub-basin between 7.08 and
8.85 Hm
3
/year was estimated. According
to the field surveys, this volume is only
available for six to eight months.
The calibrated humidity (
H
max) and
maximum infiltration (
I
max) options used
by the Temez model included ranges of
minimums, means and maximum
H
max
and
I
max. A maximum value of 9.65
Hm
3
was recorded for September, which
corresponds to the month in which the
Figure 2. Annual mean precipitation series for the Tambula-Picachos sub-basin.
1...,154,155,156,157,158,159,160,161,162,163 165,166,167,168,169,170,171,172,173,174,...195
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