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Vol.
7, No. 2 Fall 2007
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7, No. 1 Spring 2007
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6, No. 2 Fall 2006
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- An
investigation of groundwater condition by geoelectrical resistivity
method: A case study in Korin aquifer, southeast Iran
G.R.
Lashkaripour, Department of Geology, University of Sistan
and Baluchestan, Zahedan, Iran.
Abstract:
The Korin basin is
located in Sistan and Baluchestan Province in the southeast of Iran.
Rapid agricultural development in this basin has caused increase on
demand for water supply. The basin is characterized by an arid
climate with an average annual rainfall of 84 mm. The monitoring of
the groundwater level exhibits a decreasing trend of water level.
The main reason for this decline in the groundwater table is that
wells pumping from groundwater resource has exceeded natural
recharge in the recent years. In this research the aquifer of this
basin has been studied by the geoelectrical method. The need for
this research is studying groundwater conditions for protecting
groundwater supplies as a unique source of water for this area. A
resistivity survey was carried out in order to study groundwater
conditions in the shallow Korin aquifer such as depth, thickness and
location of the aquifer and the type of water. Also zones with high
yield potential have been determined based on the resistivity
information. 596 vertical electrical soundings by Schlumberger array
were conducted out at positions in 26 profiles. The resistivity
Schlumberger sounding m was carried with half-spacing in the range
of 200 m to 400.
The resistivity data confirm that the Korin aquifer
consists mainly of an alluvial aquifer. These data were used to
determine the depth and nature of the alluvium and the boundaries of
the aquifer with a reasonable accuracy. The high resistivity in the
southeast and northwest of the aquifer is due to higher water
quality and the existence of alluvial fan with coarse grain
materials. The lower resistivity in the central and northern parts
of the aquifer is due to finer materials.
Key words:
Resistivity, groundwater, aquifer, electrical sounding, Iran
- Assessment
of the Impact pf Mining on Agricultural Land using
Erosion-Deposition Model and Space Borne Multispectral Data
Sreenivas Kandrika and R.S.
Dwivedi, Agriculture & Soils Group, National Remote
Sensing Agency, (Department of Space, Govt. of India), Balanagar,
Hyderabad – 500 037, India.
Abstract: Since erosion of
mine overburden and mine dump leads to its deposition down the slope
in the catchment, an attempt was made to study the
erosion-deposition pattern in a micro watershed in part of Goa
state, south-western India using the erosion-deposition model
proposed by Mitasova et al. (1996). Information on various
parameters of the model, namely curve number, management factor,
cover factor, slope, soil erodibility, etc. was derived from the
Indian Remote Sensing satellite (IRS-IC) Linear Image Self Scanning
sensor LISS-III and PAN-merged data in conjunction with the DEM,
field check and topographic maps at 1:25,000 scale. While only 11.2%
of the area has been found to be under the protective cover of
forest, 36.31 per cent of the area is under the influence of open
cast mining, and a sizeable area is under scrubs. The impact of
mining in terms of deposition of material has been observed in an
estimated 219 ha of land, of which the agriculture land constitutes
only 10 ha. Methodology and results are discussed in detail.
- Improving
overland flow routing by incorporating ancillary road data into
Digital Elevation Models
Guy
D. Duke1, Stefan W. Kienzle1, Dan L. Johnson1,2,
James M. Byrne1, 1University
of Lethbridge, Department of Geography, 4401 University Drive,
Lethbridge, Alberta, Canada, T1K 4W1
, 2Agriculture
and Agri-Food Canada Research Branch, Environmental Health, P.O. Box
3000, Lethbridge, Alberta, Canada, T1J 4B1.
Abstract: Roads, ditches, and
culverts influence hydrological and geomorphological processes
significantly. However, most hydrological models continue to rely
solely on regional digital elevation models (DEMs) to derive
overland flow directions even though these DEMs have been shown to
contain inadequate topographical information to effectively
represent linear landscape features. This paper introduces a
methodology that improves the accuracy of grid-based overland flow
routing through the use of ancillary road, ditch, and culvert data.
The road enforcement algorithm (REA) that was developed re-routes
overland flow on either side of a road independently, thereby
enforcing linear landscape features within the flow direction
matrix. The overland flow patterns resulting from the implementation
of the REA differ significantly from flow patterns derived using
conventional GIS routing algorithms. A test application in the
prairies of southern Alberta, Canada shows the REA affects
intra-watershed runoff transport as well as the size and shape of
DEM-derived watersheds. The flow direction matrices created with the
REA can be incorporated into any grid-based hydrological model.
Keywords: Watershed
Delineation, Road, Geographic Information System (GIS), Flow
Direction, Digital Elevation Model (DEM), Hydrological Modeling
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Spatially Distributed Watershed Mapping and Modeling: Thermal
Maps and Vegetation Indices to Enhance Land Cover and Surface
Microclimate mapping (part 1) Assefa
M. Melesse1 ,Wendy D. Graham2, and Jonathan D.
Jordan2, 1Earth System Science Institute, School of
Aerospace Sciences,University of North Dakota, Grand Forks, ND,
58202-9007,2Department of Agricultural and Biological
Engineering, Institute of Food and Agricultural Sciences, University
of Florida, Gainesville, P. O. Box 110570, FL 32611-0570
Abstract: The
extent and type of watershed cover affects the movement of water in
the hydrologic cycle, thus accurate representation of the physical
and biological features of the landscape within the watershed is
required. Satellite imagery from Landsat and other satellites
provide land cover and surface microclimate information with high
temporal and spatial accuracy. The use of these data to understand
hydrologic processes depends on how accurately they are interpreted
and mapped. This paper utilizes the surface radiant temperatures
derived from the thermal band of Landsat images and vegetation
indices derived from visible, near-infrared, thermal and midinfrared
spectrums to further improve land cover and surface microclimate
mapping. The study was done on three watersheds in Florida having
mean area of 420 km2.
Landsat images from 1984 and 2000 were processed using an
unsupervised classification. Calibrated surface radiant temperatures
and vegetation indices, which indicate a strong relationship with
the ground truth data, were identified using scatter diagrams.
Surface microclimate (pixel scale) parameters (percent vegetation
cover, scaled surface temperature) were determined and their spatial
and temporal distributions were studied. The results indicate that
surface temperatures and derived vegetation indices (incorporating
the thermal and shortwave-infrared bands) were useful for
discriminating land cover classes and delineating boundaries between
wetlands and water bodies. Accuracy assessment of the classification
indicates overall accuracy of 85% was achieved with this technique.
The fractional vegetation cover decreased from 1984 to 2000 with a
respective increase in surface scaled temperature.
Keywords: surface temperature, vegetation indices, Landsat,
land cover, microclimate, unsupervised classification
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Spatially
Distributed Watershed Mapping and Modeling: GIS-based
Storm Runoff and Hydrograph Analysis: (part2)
Assefa M. Melesse1
,Wendy D. Graham2, and Jonathan D. Jordan2, 1Earth
System Science Institute, School of Aerospace Sciences,University of
North Dakota, Grand Forks, ND, 58202-9007,2Department of
Agricultural and Biological Engineering, Institute of Food and
Agricultural Sciences, University of Florida, Gainesville, P. O. Box
110570, FL 32611-0570.
Abstract:Advances in scientific knowledge and new techniques
of remote sensing permit a better understanding of the physical land
features governing hydrologic processes, and make possible
efficient, large-scale hydrologic modeling. The need for land-cover
and hydrologic response change detection at a larger scale and at
times of the year when hydrologic studies are critical makes
satellite imagery the most cost effective, efficient and reliable
source of data. In this work, remotely-sensed data and geographic
information system (GIS) tools were used to estimate the changes in
runoff response for three watersheds (Etonia, Econlockhatchee, and
S-65A subbasins) in Florida. Land-use information from Digital
Orthophoto Quarter Quadrangles (DOQQ), Landsat Thematic Mapper, and
Enhanced Thematic Mapper Plus were analyzed for the years 1984,
1990, 1995, and 2000. Spatial distribution of land-cover was
assessed over time. The corresponding infiltration excess runoff
response of the study areas due to these changes was estimated using
the United States Department of Agriculture, Natural Resources
Conservation Service Curve Number (USDA-NRCS-CN) method. A Digital
Elevation Model-GIS technique was used to predict stream response to
runoff events based on the travel time from each grid cell to the
watershed outlet. The method was applied to a representative
watershed (Simms Creek) in the Etonia sub-basin to study the effect
of land-cover on storm runoff response. Simulated and observed
runoff volume and hydrographs were compared. Isolated storms, with
volumes of not less than 12.75 mm (0.5 inch) were selected (the
minimum amount of rainfall volume recommended for the NRCS-CN
method). Results show that the model predicts the total runoff
volume with an average efficiency of 98%. The model is applicable to
ungaged watersheds and useful for predicting runoff hydrographs
resulting from changes in the land-cover.
Keywords: Runoff,
GIS, curve number, land-cover, spatially distributed
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