Altimetric and hypsometric analysis for soil and water conservation : A case study of Anjani and Jhiri river basin , Northern Maharashtra , India

RESUMEN


Introduction
The Maharashtra state, with its peculiar geohydrological, geomorphological and climatic conditions, faces multifold problems in exploration, exploitation and development of its groundwater resource in a scientific and planned manner.The operation of groundwater on a large scale for meeting the demands of rapid industrialization, agricultural sector, and domestic purpose has further aggravated the problem.Currently, Maharashtra, especially in Marathwada and Northern Maharashtra regions, faces drinking water problem and supply for drinking water in this area depends on water tankers.
The Anjani and Jhiri river basin was chosen for catchment hydrogeomorphological studies, both of which are tributaries of Girna River.Girna is one of the major tributaries of River Tapi.Anjani and Jhiri river basin covers an area of about 1243.65 Km².The present study area is located in Jalgaon district (Fig. 1).It is confined to Latitude 20° 45' N to 21° 08' N and Longitude 75° 09' E to 75° 27' E, covering topographic maps NO. 46 P/1, 46 P/5 and 46 O/8 of the Survey of India.The data on Anjani -Jhiri river basin for the present study can serve as a pilot study based on hydrology and hydrogeomorphology.
The Anjani -Jhiri river basin is characterized by an arid to semi-arid climate, and its available water depends on the amount of rainfall in this basin.The water in the basin is used for agricultural and domestic purposes.Most of the domestic water supply is through common well in rural areas funded under rural water supply schemes of the State Government.People use water from unprotected open pits (dug) well, and/or depend on supply by tankers.The scarcity of water is also one of the main reasons that compel the farmers to cultivate their land under rain fed condition annually.
The Anjani -Jhiri river basin enjoys a hot and dry summer, cool winter and fair monsoon with an average annual rainfall of about 750 mm.The Anjani River has an elevation difference of 135 m, with the highest elevation (305m) at Titvi village located at the southern edge of the catchment, and drops to its lowest elevation (170m) at the northern edge where Anjani river joins Girna river.The Jhiri River has an elevation difference of 125 m, with highest elevation of 300 m amsl near Padamalay reserve forest, and the lowest being 175 m. amsl near its confluence with the River Girna.The contour map of this area (Fig. 2) shows elevation ranging from 300m to about 180m from southern part of the basin to the confluence of Girna river.
The hydrogeomorphological study helps to explore, plan and manage the water and the natural processes which produce landforms in association with their hydrological characteristics (Babar, 2005).Geologically, the major part of study area is covered by Deccan basalt of the Cretaceous to the lower Eocene age and the rest by alluvium of the recent period (GSI, 2000).The Deccan trap lava sequence is grouped under Sahyadri Group, which was formed during the Upper Cretaceous to lower Eocene.The lava assemblage of Sahyadri group consists of alternating sequence of Pahoehoe and 'aa' flows (GSI, 1976).Dark grey massive basaltic exposed in the study area has been depicted in Figure 3.Those parts that are covered by Deccan basalts consist of amygdaloidal and vesicular basalts.
Alluvial deposits can be observed along the lower reaches of river valleys and watercourses (Fig. 4).The thickness of the alluvium ranges from less than a meter to several tens of meters (10 -100 m).Alluvium consists of unconsolidated to consolidated sand, brownish yellow silt and calcrete (locally known as kankar) along the Girna, Anjani and Jhiri rivers.In the study area, however, the alluvium is characterized by unconsolidated clays and silts that are associated with a very limited thickness (0.5-2.0m).A deep black soil covers the central part of the catchment area.Medium black soils occur within the valley and southern hills, and the alluvial basin soil (black alluvial clay) covers the northern part of the study area.Sandy soils are observed along the foothills of Satmala stretching near Padamalay hillocks.The gross and net water availabilities in the Anjani -Jhiri river basin were calculated by using equation 1 (Pilgrim and Cordery, 1993), Available water (in hectare) = Area (in ha) × Rainfall (in mm) (1) The gross and net water availabilities in the Anjani -Jhiri river basin have been presented in Table 1.

Methodology
The field work was carried out in the summer of 2012 for observing geomorphological units in the study area.After completion of the field work, we carried out the hypsometric analysis of Anjani and Jhiri river basin by Strahler methods (Strahler, 1964).The topographic maps numbered 46 P/1, 46 P/5 and 46 O/8 on 1:50000 scale from the Survey of India are considered.The SOI toposheet is geometrically rectified and georeferenced to world space coordinate system (WGS 1998) using digital image processing software (AutoCAD 2004 and Arc GIS version 9.0) and digitization work was carried out for entire basin.Percentage hypsometric curve (Strahler, 1952) that involves a ratio of relative height expressed in percentage (cumulative (hx100)/H) was plotted on ordinate, and the relative area expressed in percentage (cumulative (ax100)/A) was plotted on abscissa.Where 'a' and 'h' denote area and height between successive contours, and 'A' and 'H' denote total area and height of the basin, respectively.The areas between successive contours and their respective heights are the basic data required for the study of area-height relationship.The areas between successive contours were measured by digital planimeter, and contour heights were obtained from topographic maps used for this work.After plotting the respective value on simple arithmetic graph paper and joining all the points, a smooth line percentage hypsometric curve can be obtained.The hypsometric integral (HI) were calculated mathematically from the graph.

Hydrogeomorphological parameters
The delineation of a hydrogeomorphological parameter is aimed at demarcating the areas of groundwater recharge/discharge and potential zone for the development of groundwater (Raghu and Reddy, 2011).Alluvial plain represents the runoff zone while valley belongs to discharge zone, and the denudational hills constitute the infiltration area.It is classified into three zones on the basis of their groundwater potential zone as a) Very favorable zones b) Good to moderate zones and c) Poor zone.
The groundwater potential zones are identified with the help of geomorphological units.The morphometric data are enclosed in details and are described below (Table 2 and 3).

Dissected Plateau (DPT)
An extensive flat top and steep slopes formed over horizontally layered Deccan basalts that may be crossed by fractures, joints and lineaments are called as plateaus (Babar, 2005).These units can be expressed regarding the slope of the area, runoff characteristics, drainage density, stream frequency and relief ratio of the area (Babar, 2005).In the present study area, two plateaus were observed, i.e. moderately dissected plateau and un-dissected plateau.

Moderately dissected plateau
The soils covering in this plateau are moderately thick and well drained.High moisture capacity suggests that the irrigation requirement is moderate in the moderately dissected plateau area.The groundwater potential in these units is moderate to high.

Un-dissected plateau
The land of this unit is dissected by the streams of giving rise to un-dissected terrain consisting of flat-topped hills and steep scarps.The groundwater potential in these units is very poor (Babar, 2005).The runoff from these areas can be arrested through the construction of check dams and other strategies.

Moderately dissected plateau
Moderately dissected plateau is presented in upper part of the Anjani river catchment (Fig. 4).This unit is observed between Denudational hills and Un-dissected plateau.

Un-dissected plateau
Un-dissected plateau is distributed in lower part of the Anjani river catchment (Fig. 4).This unit is observed between moderately dissected plateau and eroded lad by stream.

Valley fills (VF)
Valley fills are linear depression presented in between the younger alluvium composed of cobbles, pebbles, gravels and sands.Valley fills are also observed in between the Denudational hills near Galapur, Khadke Bk, Mangrul and Palskhede Bk villages of upper part of the Anjani river catchment.

Denudational Hills
A group of hills with basalt as resistant rock are formed due to different erosional and weathering processes, and they occupy the low area.Denudational hills are observed in a few patches of the upper part of the Anjani river catchment (Fig. 4).

Alluvial Plains (Younger and Older alluvium)
Alluvial plains are composed of sand slit and clay layer.Fine to coarse sand layers form the potential aquifer zone.It is the most prospective hydrogeomorphological unit for groundwater exploration.younger alluvial plain can provide sufficient amount of water than older alluvial plains.Older alluvium is distributed along the northern part of the Anjani river catchment area.

Moderately dissected plateau
Moderately dissected plateau is mainly distributed in the upper part of the Jhiri river catchment (Fig. 4).This unit is observed between Denudational hills and Un-dissected plateau.

Un-dissected plateau
Un-dissected plateau is mainly located in the lower part of the Jhiri river catchment (Fig. 4).This unit is observed between moderately dissected plateau and eroded lad by stream.

Valley fills (VF)
Valley fills are found between the younger alluvium composed of cobbles, pebbles, gravels and sands.Valley fills are observed at Padmalaya and Umarde villages.

Denudational Hills
A group of hills with hard rock is formed due to different erosional and weathering processes and they occupy the region where the River Jhiri originates (Fig. 4).

Alluvial Plains (Younger and Older alluvium)
Alluvial plains with fine to coarse sand layers form potential aquifer zone.younger alluvial plain can provide sufficient amount of water than older alluvial plains.Older alluvium occurs in the northern part of the Jhiri river catchment, especially at Vaktuki, Anjan Vihire and Jhurkheda (Fig. 5).
Table 2 Linear aspects of the Anjani and Jhiri River Basin (after Golekar et al., 2013) Where

Profile analysis
Profiles drawn from the contour map is an image observation of the real environment of the landscape.The longitudinal section of the valley is called as longitudinal profile.The entire distance from source to the mouth of a particular river is considered.The graph drawn reveals the relief impact of the river course (Singh, 1997).
The longitudinal profile provides breaks in the longitudinal course of the river flow.These breaks may indicate nick points, and helps in examining the nature and control of landform development (Singh, 1997).Longitudinal profile gives geomorphologists an insight of relief and topographical impact on river flow (Babar, 2005).

Longitudinal profile of the Anjani river basin
The Anjani river originates from the Titvi village at 305 m amsl, and flows almost straight towards NE.The slope is gentle with a drop in elevation from 292m to 240m, spreading over 25 km.At the village Pashtane Budruk, it turns toward NE.After that, the channel gradient decreases steadily till its confluence with the River Girna at village Babhulgaon (Fig. 6).A study of longitudinal profile reveals the character of Anjani river.It suggests the presence of nick points at locations Chorvad (292m amsl), Pharkande (240m amsl) and Waghlud Budruk (197m amsl).The difference in elevation suggests that the river has developed "rapids".It is formed due to different erosion, relief and presence of lineament (joints).Lineament map of Jalgaon district has shown in figure 8.

Longitudinal profile of the Jhiri river basin
Jhiri river originates from village Padmalaya at 300m amsl, and it runs almost parallel with Anjani river and at Anjan Vihire village at 176m amsl it takes a NW turn and meets Girna river.The longitudinal profile curve for Jhiri river basin indicates the presence of nick points at Vikhran (212m amsl) and Vanjari Khapat (186m amsl).
The Jhiri river has a steep gradient in its earlier course with a drop from 284m to 231m up to village Umarde (8 kms away from the origin of Jhiri river), and thereafter the slope become gentle up to village Vikhran and Vanjari Khapat.There is a drop in elevation at Vanjari Khapat and the river becomes gently sloping after village Anjan Vihire.Longitudinal profile of the Jhiri river channel has shown in Figure 7.The nick points indicate that the rapids are formed due to different erosion, relief and presence of lineament (Joint).

Hypsometric (area-altitude) analysis
The hypsometric curve is a normalized cumulative frequency distribution of elevation (Strahler, 1964).This curve is constructed by summing the number of data points higher than incremental thresholds of elevation, starting at the maximum elevation.Classically, hypsometric analysis has been used to differentiate erosional landforms at different stages of their evolution (Strahler, 1952;Schumm, 1956).The hypsometric analysis is necessary to determine the runoff, recharge, and storage conditions of the ungauged basins and is helpful for hydrogeological investigations.Hypsometric curves show the relationship between relative heights (h/H) and relative areas (a/A).
The relative area is a ratio of the area above a particular contour to the total area of the basin.According to Sarangi et al. (2001), the relative elevation is calculated as the ratio the height of a given contour (h) to the maximum basin elevation (H).Hypsometry reveals the relationship between altitude and basin area to understand the degree of dissection and the stage of the erosional cycle (Strahler, 1952;Schumm, 1956).Area height curve, hypsometric curve, and percentage hypsometric curve are used to obtain the relationship between altitudes and area of the basin.
Convex-up curves with high integrals indicate typical youth, undissected (disequilibrium stage) landscapes, while smooth, s-shaped curves crossing the center of the diagram represent the characteristics of mature (equilibrium stage) landscapes and concave curves with low integrals exhibit old and deeply dissected landscapes (Strahler, 1952).

Hypsometric (area-altitude) analysis of the Anjani river basin
The Hypsometric curve of Anjani river (Fig. 9) suggests that the larger part of the area is moderate to gentle sloping.The curve can be characterized as mature/equilibrium stage of landscape development.The curve shows 1) elevation in 15 % of the area ranges between 300m -280m 2) 50 % between 280m -240m and 3) 35 % between 240m-180m.These results indicate that about 85% of the study area is moderate to gently sloping and about 15 % area is steep sloping (Fig. 6).The hypsometric integral (HI) is the area beneath the hypsometric curve which relates the percentage of total relief to its cumulative percentage.This provides a measure of the distribution of landmass volume remaining beneath or above a basal reference plane.
Integration of the hypsometric curve gives the hypsometric integral.Pike and Wilson (1971) has mathematically defined the elevation-relief ratio E as Where, E is the elevation-relief ratio equivalent to the hypsometric integral HI; Elev mean is the weighted mean elevation of the basin estimated from the identifiable contours of the delineated basin; Elev min and Elev max are the minimum and maximum elevations within the basin, the hypsometric integral is expressed in percentage units.
The hypsometric curves and HI values give valuable information about the geological stage of the development of a basin.According to Strahler (1952) and Kusre (2013) In in-equilibrium (youthful) stage, the basin is still under developed.The equilibrium stage is the mature phase of basin development, and the monadnock phase occurs, particularly when isolated bodies of resistant rock from major hills (monadnock) are found above the subdued surface.It is a rejuvenation stage controlled by structural features (Kusre, 2013).Narayanpethkar et al. (1991) and Sable et al. (2009) used the hypsometric integrals for understanding groundwater recharge in different basins of basaltic terrains.The characteristics of hypsometric integrals of the watershed were also reported by Vivoni et al. (2008).They stated that the watershed with higher HI values indicated higher soil moisture, whereas a watershed with lower HI values is characterized by soil moisture being concentrated at the shallow depth.This means that watershed with lower HI values has less total runoff contributed from surface runoff.Whereas, watershed with higher HI values shows subsurface runoff is major process contributing the total runoff.

Figure 1 .
Figure 1.Location map of the study area

Figure 2 .Figure 3 .
Figure 2. Contour Map and river flowing in the Study area

Figure 10 .
Figure 10.Hypsometric Curve (Jhiri river) , it can be classified as a) HI ≥ 0.6 = The basin is in-equilibrium (youthful) stage.b) 0.35 ≤ HI < 0.6 = The basin is at equilibrium stage.c) HI< 0.35 = The basin is at monadnock stage.