Objectives of the Study
The present study aims to analyze the impacts of LULC changes spatially and
temporally. It also addresses the influence of LULC in the runoff of a medium size
urban catchment area, in India, for different rainfall return periods of an ungauged
basin. The objectives of the study are as follows:
1. To estimate the rainfall intensity for a medium size urban catchment area using
statistical techniques
2. To study the changes in LULC of a medium size urban catchment area and the
impacts on urban runoff
3. To develop floodplain and hazard maps for different return periods
4. To recommend suitable planning and designing of the drainage system in the
catchment area
Scope of the Study
The work is to be carried for the Koraiyar basin passing through Tiruchirappalli city,
a medium size city. Flood studies for a 100 years return period have not been done.
An integrated flood modeling approach and LULC analysis have not yet been
attempted in the Koraiyar Basin. The modeling approach adopted for this study
can be adopted to basins of similar land use and climatic conditions.
Study Area
The Koraiyar River and its catchment lie between latitude 10
32
0 40.24
00 N and
10
48
0 16.81
00 N and longitude of 78
32
0 23.94
00 E and 78
39
0 48.58
00 E in
Tiruchirappalli city, South India. The river originates from the Othakkadai Karupur
Redipatti hills in Manaparai taluk of Tiruchirappalli district and finally flows into the
Uyyokondan channel in the center of Tiruchirappalli city, Tamil Nadu (Fig. 3.1).
The river basin has a subtropical climate. There is no significant temperature
difference between summer and winter, with summer (March–May) having an
extreme temperature of 41
C and a least of 36
C; winter (December–February)
generally being warm but pleasant with temperatures ranging from 19
C to 22
C.
Hot, humid, dry summers and mild winters are the main climatic features of the
basin. The rainy season that falls between October and December brings rain mostly
from the northeast monsoon. The river flows through Manaparai, Thuvarankurichi,
and Viralimalai, and the total length of the main river is 75 km, with a catchment area
of 1498 km
2 . The average annual rainfall for the Koraiyar urban catchment is about
757.40 mm to 866.70 mm. The surplus water flows through Puthur weir outlet in the
left bank of the Uyyakondan River and traverses the Kodamurutty River for 6 km
3 Flood Risk Assessment for a Medium Size City Using Geospatial Techniques with. . .
55
The present study aims to analyze the impacts of LULC changes spatially and
temporally. It also addresses the influence of LULC in the runoff of a medium size
urban catchment area, in India, for different rainfall return periods of an ungauged
basin. The objectives of the study are as follows:
1. To estimate the rainfall intensity for a medium size urban catchment area using
statistical techniques
2. To study the changes in LULC of a medium size urban catchment area and the
impacts on urban runoff
3. To develop floodplain and hazard maps for different return periods
4. To recommend suitable planning and designing of the drainage system in the
catchment area
Scope of the Study
The work is to be carried for the Koraiyar basin passing through Tiruchirappalli city,
a medium size city. Flood studies for a 100 years return period have not been done.
An integrated flood modeling approach and LULC analysis have not yet been
attempted in the Koraiyar Basin. The modeling approach adopted for this study
can be adopted to basins of similar land use and climatic conditions.
Study Area
The Koraiyar River and its catchment lie between latitude 10
32
0 40.24
00 N and
10
48
0 16.81
00 N and longitude of 78
32
0 23.94
00 E and 78
39
0 48.58
00 E in
Tiruchirappalli city, South India. The river originates from the Othakkadai Karupur
Redipatti hills in Manaparai taluk of Tiruchirappalli district and finally flows into the
Uyyokondan channel in the center of Tiruchirappalli city, Tamil Nadu (Fig. 3.1).
The river basin has a subtropical climate. There is no significant temperature
difference between summer and winter, with summer (March–May) having an
extreme temperature of 41
C and a least of 36
C; winter (December–February)
generally being warm but pleasant with temperatures ranging from 19
C to 22
C.
Hot, humid, dry summers and mild winters are the main climatic features of the
basin. The rainy season that falls between October and December brings rain mostly
from the northeast monsoon. The river flows through Manaparai, Thuvarankurichi,
and Viralimalai, and the total length of the main river is 75 km, with a catchment area
of 1498 km
2 . The average annual rainfall for the Koraiyar urban catchment is about
757.40 mm to 866.70 mm. The surplus water flows through Puthur weir outlet in the
left bank of the Uyyakondan River and traverses the Kodamurutty River for 6 km
3 Flood Risk Assessment for a Medium Size City Using Geospatial Techniques with. . .
55