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Contents
Vol.
7, No. 2 Fall 2007
Vol.
7, No. 1 Spring 2007
Vol.
6, No. 2 Fall 2006
Vol.
6, No. 1 Spring 2006
Vol. 5, No. 2 Fall 2005
Vol.
5, No. 1 Spring 2005
Vol.
4, No. 2 Fall 2004
Vol.
4, No. 1 Spring 2004
Vol.
3, No. 2 Fall 2003
Vol. 3, No. 1 Spring
2003
Vol. 2,
No. 2 Fall 2002
Vol. 2,
No. 1 Spring 2002
Vol. 1, No. 1 Fall 2001
Submission Guidelines for Authors
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Copyright Policy
Copyright © 2001 - 2008
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All rights reserved.
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| Prioritizing
Vegetative Buffer Strip Placement in an Agricultural Watershed |
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Sharon
Vennix1 and William Northcott2, 1Former
Graduate Student, 2Assistant Professor,
Department of Biosystems and Agricultural Engineering, Michigan
State University, 218 Farrall Hall,
East
Lansing, MI 48824
Abstract:
In this study, the
Agricultural Nonpoint Source Pollution Model (AGNPS) was used to
determine locations of vegetative buffer strip effectiveness on
reducing sediment load within the East Bad Creek (EBC)
watershed, a 690 ha agricultural watershed located mid Michigan.
Modeling scenarios consisted of simulating the hydrology and
sediment transport throughout the EBC watershed on a baseline
scenario (no buffer) and with a 30-meter vegetative buffer strip
placed around each stream segment (buffer strip scenario). The
model’s results showed a 17% decrease in sediment load at the
watershed’s outlet for a 10yr-24hr storm. As a result, the
placement of buffer strips within the watershed was prioritized
on three different scales. The reduction of sediment due to
buffer strips was analyzed on a stream segment level, a field
boundary level, and on a cell-by cell basis. The stream segment
buffers and field buffers were ranked on their overall ability
to reduce sediment load into the stream. The reduction in
sediment yield from the stream segments and the fields varied
from 3.49 to 58.54 tons and 0 to 19.31 tons respectively. The
cell results were evaluated by highlighting 0.5 tons – 3.63 tons
of sediment throughout the watershed, deeming those buffered
cells efficient. The cell-by-cell evaluations highlighted
specific critical areas of buffer efficiency on a 30-meter
resolution where the stream segment and field evaluations
identified specific stream segments and fields to target for
buffer placement. The AGNPS model along with the Arcview
Non-Point Source Model (AVNPSM) GIS interface demonstrates that
agricultural watersheds can be quickly and efficiently evaluated
to target locations of buffer placement. Therefore, helping
watershed managers implement vegetative buffer strips in
site-specific areas within the watershed to employ efficient
implementation of conservation management programs.Keywords:
AGNPS, Buffer Strips, Sediment, GIS
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| GENERALISED
LONG DURATION PROBABLE MAXIMUM PRECIPITATION (PMP) ISOHYETAL MAP
FOR PENINSULAR MALAYSIA |
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Abdullah
Al-Mamun and Alias Hashim,
Jurutera
Perunding Zaaba, 17 Jalan Daud, Kg. Baru, 50300 Kuala Lumpur,
Malaysia
Abstract:
Isohyetal maps were prepared to estimate
Probable Maximum Precipitation (PMP) for long duration storms in
Peninsular Malaysia. Historical storms of 1, 3 and 5-day
durations from 21 rainfall recording stations operated by
Malaysian Meteorological Service (MMS) were identified and
analysed to calculate the PMP vales. Maximum rainfall for 1, 3
and 5-day storms in the Peninsula were recorded as 809, 1272.9
and 1494 mm, respectively. The widely used and most reliable
hydrometeorological method was used to derive and transpose the
PMP values from the storm locations to all MMS stations in the
Peninsula. Maximum transposed PMP for a particular duration was
obtained for six selected historical storms.
Rectified Skew Orthomorphic (RSO) coordinates of
the rainfall stations and point PMP values were used for the
Kriging method to generate the PMP envelop curves. The
enveloping isohyetal lines were further adjusted and smoothen to
consider the effect of topographical and geographical effect on
the PMP values. Calculated point PMP values for 1, 3 and 5-day
storms can, respectively, be as high as 1149, 1808 and 2121 mm
in West Malaysia. These isohyetal maps shall give direct and
fast estimate for PMP values even for the catchments where no
rainfall gauging stations are available.
However, results obtained in this study is
applicable for the catchments located at elevation lower than
200 m mean sea level (MSL), and until any storm larger than the
selected (in this study) occur in Peninsular Malaysia.
Keywords:
Probable Maximum Precipitation (PMP),
Storm Duration, Storm Maximization, Historical Rainfall,
Transposition and Isohyetal Map.
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| Modeling
Groundwater Flow for the Delineation of Wellhead Protection Area
around a Water-well at Nachole of Bangladesh |
Md. Mizanur Rahman1 and Shamsuddin Shahid2,
1 Postgraduate Student, 2Assistant Professor
Department of Applied Physics & Electronics,
Rajshahi University, Rajshahi-6205, Bangladesh.
AAbstract:
Delineation of
wellhead protection area is an important component of groundwater
contamination protection strategy to prevent probable environmental
and health hazards. Modeling of ground water infiltration and
movement in the wellhead area is a critical part of any effective
wellhead protection program. Such models depend on an accurate
description of the aquifer in the wellhead area for the reliable
estimation of contaminant travel times and defining protection area.
In this paper, a two-dimensional groundwater flow model is proposed
for the estimation of contaminant travel time to water well and
delineation of wellhead protection area. The model is applied for
the demarcation of wellhead zone of a water-well situated at Nachol
in Chapai Nawabganj District of Bangladesh. The parameters required
for the modeling of groundwater flow and delineation of Wellhead
protection area are obtained from borehole litholog and available
literatures. The study shows that to ensure clean groundwater supply
for a period of 10 years it is essential to impose restrictions on
land use activities in an area of 1.91 km2
around the water well.
Keywords :
Groundwater Flow Modeling,
Zone of Contribution, Zone of influence, Wellhead Protection Area.
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| Spatial
Variability of Groundwater Recharge - I. Is it really variable? |
P de Silva, Department of Agricultural & Plantation
Engineering, Open University, Nawala, Nugegoda 10250, Sri Lanka
Abstract:
The spatial variability of recharge is an important consideration in
estimating recharge especially as all methods of estimating it are
'point' estimates and in most places recharge varies in space. This
paper along with the accompanying paper attempts to find a suitable
answer to the question of taking this variability into account in
estimating groundwater recharge. This paper attempts to determine if
recharge is actually varying in space and that this is 'true'
variability and that it is not an artefact of the method used for
estimating recharge. It also pulls together information on spatial
variability of recharge reported by various workers in the
literature, in order to determine if recharge is truly variable in
space.Keywords:
Spatial
variability, Groundwater recharge, Sri Lanka
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| Spatial Variability of
Groundwater Recharge - II. Factors Affecting Variability and Taking
Account of it in Estimating Recharge |
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P de Silva,
Department of Agricultural & Plantation Engineering,
Open University, Nawala, Nugegoda 10250, Sri Lanka
Abstract:
The accompanying paper provided evidence
to suggest that spatial variability of groundwater recharge is
‘true’ variability. This paper attempts to determine the major
causes of such variability even at small distances, if there appears
to be a frequency distribution to this spatial variability and
lastly if it is possible take this variability into account in
estimating recharge in an area. The clay content of the top soil
appears to have a significant effect on recharge. The spatial
variability of recharge appear to be log normally distributed and a
way is shown where simple statistics can be used to take account of
the spatial variability in estimating recharge.
Keywords:
Spatial variability, Groundwater recharge, Sri Lanka
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JOSH