curva de hypsometria

INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES

Volume 2, No 1, 2011

Copyright 2010 All rights reserved Integrated Publishing services

Research article ISSN 0976 4380

Submitted on September 2011 published on November 2011 241

Hypsometric Analysis of Varattaru River Basin of Harur Taluk,

Dharmapuri Districts, Tamilnadu, India using Geomatics Technology Sivakumar. V

1, Biju. C

1, Benidhar Deshmukh

2

1- Geomatics Solutions Development Group, Centre for Development of Advanced

Computing (C-DAC), Pune - 411007, India.

2- Discipline of Geology, School of Sciences, IGNOU, New Delhi, India.

[email protected]

ABSTRACT

Hypsometric analysis describes the distribution of horizontal cross-sectional area of river

morphology with respect to elevation (area-altitude analysis). Morphology of a river basin

plays primary role in the dynamics of surface and subsurface water runoff generation. It is

also an essential tool to measure and represent the form of a watershed and its evolution. Aim

of the paper is to carry out the Hypsometric analysis of Varattaru river basin of Harur taluk,

Dharmapuri district, Tamilnadu using remote sensing and GIS technologies. Hypsometric

data were derived and analyzed for each of the divided sub zone of Varattaru river basin from

the 30 meter ASTER DEM. It was found that high-medium hypsometric integrals/elevation-

relief ratios indicating a youthful to mature stage landscape, medium to complex

denudational processes, the linear river morphological changes of this river basin and remote

sensing data and open source tools it becomes less tedious to make hypsometric integrals and

curves. This paper emphasizes the rainwater harvest practices and management for the

watershed at suitable locations for controlling further erosion, reducing the runoff and

increases the groundwater potential.

Keywords: Hypsometric analysis, Geomatics technology, Harur, Varattaru river

1. Introduction

Hypsometric analysis (area-altitude analysis) is the study of the distribution of horizontal

cross-sectional area of a landmass with respect to elevation (Strahler, 1952). Naturally,

hypsometric analysis has been used to differentiate between erosional landforms at different

stages during their evolution (Strahler, 1952, Schumm, 1956). The statistical characteristic in

the hypsometric analysis includes the hypsometric integral (I), hypsometric curve,

hypsometric skewness, etc. (Wei Luo et al, 2003). Hypsometric integrals and hypsometric

curve are important indicators of watershed conditions (Ritter et al. 2002). The hypsometric

integral is the area beneath the curve, which relates the percentage of total relief to

cumulative percent of area and shape of the hypsometric curve, indicates age of the

catchment.

Hypsometric integrals and curves can be interpreted in terms of degree of basin dissection

and relative landform age: Convex-up curves with high integrals are typical for youthful

stage, undissected landscapes; smooth, s-shaped curves crossing the center of the diagram

characterize mature (equilibrium stage) landscapes, and concave-up with low integrals typify

old and deeply dissected landscapes (Strahler, 1952). It was also found by Strahler (1952)

that the hypsometric integral is inversely correlated with total relief, slope steepness, drainage

density and channel gradients. This provides a measure of the landform distribution of

landmass volume remaining beneath or above a basal reference plane. The hypsometric

Hypsometric Analysis of Varattaru River Basin of Harur Taluk, Dharmapuri Districts, Tamilnadu, India

using Geomatics Technology

Sivakumar. V, Biju. C, Benidhar Deshmukh

International Journal of Geomatics and Geosciences

Volume 2 Issue 1, 2011 242

integral helps in explaining the erosion that had taken place in the watershed during the

health of watersheds. There is a lack of hypsometric analysis based studies for small river

basin like Varattaru river to analyze the watershed health, which is due to the tedious nature

of data acquisition and analysis involved for estimation. However, due to advent of remote

sensing data (including derived digital elevation models) and open source GIS tools, the

estimation process becomes easier than conventional methods. Considering the above facts,

this study was undertaken to highlight the rainwater harvest practices and management for

the watershed at suitable locations for controlling further erosion, reducing the runoff,

increases the groundwater potential and stages of landform development in the Varattaru

river basin.

2. Study Area

Varattaru river basin is located in the southeastern part of Harur Taluk, Dharmapuri district,

TamilNadu. It is located between Latitudes 1112 and Longitudes 78 79 (Figure 1).

Varattaru river is one of the major tributary of Vaniar river. . This river originates from

Chitteri hills and passes through Velimadurai, Keraipatti, Ellapudiampatti and joins the

Vaniar river at north east of Harur town. River basin boundary derived from Berkley

tophosheet scale 1:25000. The river basin has a total geographical area of 1005 sq km.

Varattaru river pass through major geomorphologic units such as valley fills denudation hills,

weathered pediplains, etc. Geologically the area broadly consists of Charnockite and Gneissic

rock. The important soil types encountered in the area can be broadly categorized into black

to mixed loam and red sandy soils. Elevation varies from 330m to 1300m approximately. The

yearly average rainfall observed is ~895 mm in the basin.

Figure 1: Study area map

3. Data and Method

ASTER DEMs were downloaded from USGS via internet and adjacent DEM were mosaicked

together because some part of basin span across few quadrangles. Landsat ETM 30m data

were downloaded to know the land use land cover pattern of this basin






(http://www.landcover.org/index.shtml). Landsat ETM-MSS data of 30m spatial resolution

were fused with pan data of 15m spatial resolution to obtain detailed landcover information.

ASTER DEMs and Landsat fused imageries were clipped with reference to approximate

basin boundary (Figure 2 & 3). Hypsometric cure was derived for Varattaru river basin from

the 30m ASTER DEM. Figure 3 shows the DEM that was used for the landscape

characterization of the study area as suggested by Kokkas (2008). Calculation of the

hypsometric integral (i.e area under the hypsometric curve) was automated in System for

Automated Geoscientific Analyses (SAGA), an open source software using the hypsometric

function in morphomertric analysis (http://www.saga-gis.org). Integration of the hypsometric

curve gives the hypsometric integral (I). Pike and Wilson (1971) proved mathematically that

the elevation-relief ratio (E) which is defined as Integration of the hypsometric curve gives

the hypsometric integral (I). Pike and Wilson (1971) proved mathematically that the

elevation-relief ratio (E), which is defined as

E = (mean elevation minimum elevation)/ (maximum elevation minimum elevation)

is identical to the hypsometric integral (I) but has the advantage that it is much more easy to

obtain numerically (Singh et al. 2008). The output table contains the relative elevation,

relative area, absolute elevation and absolute area information. The output data were

normalised and generated hypsometric curve. Elevation contour was derived from DEM and

overlaid on Landsat ETM (Figure. 4). Slope map was derived from ASTER DEM for

understanding the topography relief variation (Figure. 5).

Figure 2: PAN-merged Landsat ETM - FCC Satellite imagery of study area. Reddish black

color shows vegetation cover including forest cover. Light red green color shows

agriculture and scrubs.






Figure 3: ASTER DEM of study area (Unit In meter)

Figure 4: Elevation contour overlaid on satellite image.






Figure 5: Slope map.

4. Results and Discusion

Figure 6 shows the results of hypsometric analysis for the Varataru river basin. Hypsometric

curves show high-medium hypsometric integrals/elevation-relief ratios indicating a youthful

to mature stage landscape. Due to run-off there is more kinetic energy, the ground is cut away

faster so the curve of elevation versus area falls off more quickly. Sapping is a lower energy

process and so its curve appears rather flat at first and then falls off. In the study area,

approximately more than 80% of area (or volume) lay at elevations than mean elevation. It

was also observed that there was a combination of moderate convex-concave and slightly S

shape of the hypsometric curves for the Varattaru river basin. This could be due to the soil

erosion from the basin and down slope movement of topsoil and bedrock material, washout

of the soil mass and cutting of stream banks. The hydrologic response of the basin has

youthful stage, will have high to moderate rate of erosion during peak runoff and need

appropriate soil and water conservation measures. The hypsometric curve expresses medium

to complex denudational processes and the linear river morphological changes of this river

basin. This study suggests that many artificial recharge structures are suggested at many

places to increase the groundwater potential and to control the soil erosion. Low hypsometric

integral indicates suitable locations for recharge structures (Keripatti, Kilaparai,

Ellapudiampatti and near Harur) and moderate values are suitable sites for preventing soil

erosion and also runoff.






Figure 6: Hypsometric curve as obtained for river Varattaru.

5. Conclusions

This study highlights the importance of hypsomertic analysis for rainwater harvest practices

and management for the river basin at suitable locations for controlling further erosion,

reducing the runoff, increasing the groundwater potential and various stages of landform

processes in the Varattaru river basin. So with remote sensing data and open source tools it is

becomes less tedious to make hypsometric integrals and curves. Though, the available data

and the software module has some limitations, it can be considered to be an encouragement

for further study.

References

1. Kokkas, N.A. and Miliaresis, G., (2008), Geomorphometric Mapping Of Grand

Canyon From The 1-Degree USGS DEMs, ISPRS, proceedings, XXXV,

www.isprs.org/proceedings/XXXV/congress/comm4/papers/460.pdf, Accessed on

20-Feb-2011.

2. Pike, R.J. and Wilson, S.E. (1971), Elevation-relief ratio, hypsometric integral and

geomorphic area-altitude analysis, Geological Soc. Am. Bull., 82:1079-1084.

3. Ritter, D.F., Kochel, R.C. and Miller, I.R. (2002), Process Geomorphology.

McGraw Hill, Boston.

4. Strahler, A.N. (1952), Hypsometric (area-altitude) analysis of erosional

topography, Geological Soc. Am. Bull., 63, pp 1117-1141.






5. Schumm, S.A. (1956), Evolution of drainage systems and slopes in bad-lands at

Perth Amboy, New Jersey, Geol. Soc. Am. Bull., 67, pp 597646.

6. Singh, O., Sarangi, A. and Sharma, M.C. (2008), Hypsometric integral estimation

methods and its relevance on erosion status of north-western Lesser Himalayan

Watersheds, Water Res. Mgt., 22, pp 1545-1560.

7. Wei Luo and John M. Harlin, (2003), Theoretical Travel Time Based on Watershed

Hypsometry, Journal of the American Water Resources Association, pp 785 792.

Documents

curva de hypsometria