Download Title: use of gis in rainwater harvesting Name : otieno kerubo m faith

TITLE: USE OF GIS IN RAINWATER
HARVESTING
NAME : OTIENO KERUBO M FAITH
REG. NO. :F19/1454/2010
Supervisors : Mr. S. Matara
Mrs. Tabitha Njoroge
OUTLINE
Problem statement
 Objectives
 Background
 What is rainwater harvesting?
 Progress and Way forward
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PROBLEM STATEMENT
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Water is one of the basic necessities of life that are
required daily. Without it life would not be the same.
Some daily activities would come to a halt. The
resource, water should therefore be available at all
times. In arid and semi arid areas, this is just a
mirage.
This study seeks to solve the situation by determining
potential/suitable rainwater harvesting sites using
GIS.
The purpose of this project is therefore to map out
these harvesting sites and provide the information,
which can then be used by the responsible authorities
to put these water harvesting systems into place. For
this purpose, the combined effort of GIS analysis and
field surveys can be used. This report describes the
mapping by GIS (Geographic Information Systems),
of the rainwater harvesting potential in Seme
OBJECTIVES
Main Objective
 The main objective is to use GIS to map potential
Rainwater Harvesting sites in Seme Sub-county, and
thereby provide a tool for advocacy and decision
support for RWH in the area.
Specific Objectives
 To perform a review of water harvesting techniques
(rooftop RWH, surface runoff into ponds, in-situ
RWH)
 To prepare a GIS Geo-database of the surface water
situation in Seme Sub-county
 To apply the geo-database in mapping potential RWH
sites in Seme Sub-county
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BACKGROUND
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In the area of study, which is Seme sub-county, there is a
big water problem since the area experiences erratic
rainfall. The activities that take place in the area include
agriculture, livestock rearing and other economic activities
and daily activities that require water.
When the rain falls in the rainy season, only a few people
store the water in tanks since the area is largely rural and
most people cannot afford water tanks let alone iron sheet
roofs.
Later on in the dry season, the water problem comes back
and people have to walk long distances to get water and
even spend a fortune on water, by buying from people with
boreholes.
It is because of this that I took up the challenge to help in
solving the problem as the area has a lot of potential for
rainwater harvesting.
RAINWATER HARVESTING
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Rainwater harvesting is the process of accumulation
and storage of rainwater and runoff for re-use on site
or away from the rainfall site using various
technologies.
The different technologies that could be used in doing
this include:
In situ
Internal (micro) catchment RWH-the field is also the
catchment area (CA is less than 1000m2)
External (macro) catchment RWH-many fields share
water trapped from a large catchment area(1000m2200ha).
This project looks mainly at the macro catchment
techniques.(plastic lined underground tanks, water
pans, tanks,rock catchments).
RAINWATER HARVESTING EXAMPLES
DATA NEEDED AND DATA COLLECTED
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The key factors that determine whether a site is
suitable for rainwater harvesting are listed
below:
Information on precipitation in the area
Population data, population density
Topography data (contours from topographic map
of the area)
Data on Settlement
Soil data(soil depth, soil pH, soil texture)
Land use and land cover data
Rivers and roads in the area
METHODOLOGY FLOWCHART
CRITERIA FOR ANALYSIS
Procedure for this project can be listed basically as
stated below:
1.
Collecting datasets for input into the GIS model
2.
Assigning weights to each of the datasets
3.
Combining and analyzing the selected datasets.
The analysis will be done using the following methods:
i.
Weighted overlay analysis
ii.
Land cover data analysis
iii. Surface hydrology modeling
iv.
Buffer analysis
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PROGRESS AND WAY FORWARD
Data acquisition
 Data editing
 DEM creation
 Data analysis which includes:
 Hydrological modeling
 Slope map creation (aspect map)
 Soil and Land cover data analysis
(reclassification)
 Creating a Rainwater harvesting potential sites
map
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Thank
you!