Investigations on surface and subsurface drainage requirements at regional scale

INVESTIGATIONS ON SURFACE AND SUBSURFACE DRAINAGEREQUIREMENTS AT REGIONAL SCALEy

KRISHAN KUMAR1, J. SINGH1 AND S. K. GUPTA2*

1Department of Soil and Water Engineering, CCS Haryana Agricultural University, Hisar-125 004, India2Division of Irrigation and Drainage Engineering, Central Soil Salinity Research Institute, Karnal-132 001, India

ABSTRACT

Amongst the three drainage basins in Haryana (India), the inland drainage basin is most prone to surface stagnation,

rise in groundwater table and soil salinization. In order to understand the surface and subsurface drainage

requirements of this basin, a number of groundwater regime maps (groundwater table contour map, depth to

groundwater table map, groundwater fluctuation map and groundwater quality map) were prepared to assess

long-term groundwater table behaviour in a part (comprising Rohtak and Jhajjar districts) of this basin for the

period 1984–98. Groundwater movement was observed to occur towards the central part of the study area, a

possible cause of waterlogging and degradation in groundwater quality. The groundwater levels during the past two

and a half decades (1974–98) registered a rise varying from 1 to 19m with an average rise of 21 cmyr�1. The

rainfall data of Rohtak and Jhajjar districts for the period (1975–98) were analysed for different frequencies of

exceedance to determine 1, 2 and 3 days of consecutive rainfall. The surface drainable surplus was calculated taking

into account the water storage in the soil profile, infiltration rates and evaporation that varied from 30–35, 35–40

and 5mm day�1 respectively. The drainable surplus for consecutive 1, 2 and 3 days’ rainfall for a 5-year return

period was 161, 113 and 0m3 s�1 respectively. The existing surface drainage system with a capacity of 170m3 s�1

and with availability of dead storage, could handle 1 and 2 days’ consecutive rainfall for a 5-year return period

when full initial storage of 30–35 cm (equivalent to 50% of the available moisture) is available in the soil

profile. From the groundwater regime maps, it was also estimated that nearly 16% of the study area (57 932 ha)

required treatment with subsurface drainage. Therefore, a groundwater model (SWAP) was used to predict the

subsurface drainable surplus considering various inputs related to the water balance of the area. The

subsurface drainable surplus over the simulated years ranged between 0.4 and 1.92mm day�1. This range is

quite close to the recommended range of the subsurface drainage coefficient for this region on the basis of field

trials. The study of irrigation and drainage maps of the area revealed that there is a need to strengthen field surface

drains and introduce subsurface drainage in the area. As such, the methodology proposed in this paper could be used

to investigate drainage requirements on a regional scale. Copyright # 2006 John Wiley & Sons, Ltd.

key words: waterlogging; surface drainage; subsurface drainage; drainable surplus; modelling

Received 7 October 2005; Revised 4 February 2006; Accepted 11 July 2006

RESUME

Parmi les trois bassins de drainage de Haryana (Inde), le bassin interieur est le plus enclin a la stagnation des eaux

de surface, a une remontee de la nappe et a la salinisation du sol. Afin de comprendre les besoins de ce bassin en

drainage de surface et souterrain, un certain nombre de representations cartographiques des regimes des eaux

IRRIGATION AND DRAINAGE

Irrig. and Drain. 55: 491–500 (2006)

Published online 7 November 2006 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/ird.272

*Correspondence to: Dr S. K. Gupta, Head, Division of Irrigation & Drainage Engineering, Central Soil Salinity Research Institute,Karnal-132 001, India. E-mail: [email protected] sur les besoins de drainage de surface et souterrain a l’echelle d’une region de l’Inde.

Copyright # 2006 John Wiley & Sons, Ltd.

souterraines ont ete etablies (contour, profondeur, fluctuations et qualite) pour evaluer le comportement a long

terme de la nappe dans une partie (comprenant les districts de Rohtak et de Jhajjar) de ce bassin pour la periode

1984 a 1998. Des mouvements ont ete observes dans la partie centrale de la zone d’etude, representant une cause

possible d’engorgement et de degradation de la qualite de l’eau souterraine. Les niveaux de la nappe pendant 25 ans

(1974–1998) montrent une remontee variant entre 1 et 19m, avec unemoyenne de 21 cm par an. La pluviomerie des

districts de Rohtak et Jhaijar pendant la meme periode a ete analysee de maniere a mettre en evidence des

frequences de depassement de 1, 2 et 3 jours de pluies consecutifs. Le volume d’eau necessitant un drainage de

surface a ete calcule en prenant en compte la reserve d’eau du sol, des taux d’infiltration de 30–35 a 35–40 cm et

d’evaporation de 5mm/jour respectivement. L’excedent drainable pour des pluies de 1, 2 et 3 jours consecutifs sur

une periode de retour de 5 annees etait de 161, 113 et 0m3/s respectivement. Avec une capacite de 170m3/s et une

certaine disponibilite de stockage, le systeme de drainage de surface existant pouvait traiter des periodes pluvieuses

de 1 et 2 jours sur une periode de retour de 5 annees lorsque la capacite de stockage initial d’eau dans le sol etait de

30–35 cm (equivalent a 50% de l’humidite disponible). A partir des cartes des regimes des eaux souterraines, on a

pu egalement estimer que pres de 16% de la zone d’etude (57 932 ha) demandait un drainage souterrain. En

consequence, un modele souterrain (SWAP) a ete employe pour prevoir l’excedent drainable en souterrain en

fonction de diverses donnees d’entree liees au bilan hydrique de la zone. Pour les annees simulees, cet excedent

variait entre 0,4 et 1,92mm/jour, une ‘fourchette’ assez proche de celle recommandee dans la region sur la base

d’essais de terrain. L’etude des cartes d’irrigation et de drainage de la zone a montre le besoin d’y renforcer les

drains de surface et d’y introduire le drainage souterrain. En tant que telle, la methodologie proposee dans cet

article pourrait etre utilisee pour analyser les besoins de drainage a l’echelle d’une region. Copyright# 2006 John

Wiley & Sons, Ltd.

mots cles: engorgement; drainage de surface; drainage souterrain; excedent drainable; modelisation

INTRODUCTION

Haryana (India) has been at the receiving end of nature with the expanding deserts and floods and droughts visiting

the state at regular intervals since 1947. In this context, expansion of irrigation after the creation of the state in 1966

played a very dominant role and turned this food grain deficit state into a food grain surplus one. However,

expansion of irrigation brought in its wake waterlogging and soil salinity, affecting production and productivity

over a large part of the state. The worst affected part is the inland alluvium basin occupying 22.4% of the state area,

the largest of three groundwater sub-basins in Haryana state. Some of the problems of the basin relate to topography

(saucer-type depression), restricting gravity outflow of runoff during the monsoon season. The groundwater inflow

occurs from all sides, resulting in a rise in the groundwater table and deterioration in groundwater quality. A

number of studies have been carried out on this basin (Agarwal and Khanna, 1983; Singh and Singh, 1983).

Considering the observations made in these studies, a serious attempt to address the problem of waterlogging and

soil salinity was initiated by the Central Soil Salinity Research Institute (CSSRI), Karnal at Sampla in Rohtak

district (Gupta, 1985; Rao et al., 1986). Since the CSSRI study covered less than 100 ha, regional problems

continued to flare up at regular intervals. Therefore, an attempt was made to investigate the surface and subsurface

drainage requirements of a part of the inland drainage basin through field-collected secondary data and modelling.

The main objective was to suggest a technology to assess the surface and subsurface drainable surplus so that an

integrated drainage system could be designed and disposal infrastructure created. This paper outlines this strategy

through the case study of the part of the inland drainage basin and comments upon the outputs through field

experiences of the research organizations and line departments that are active in this area.

METHODOLOGY

The state of Haryana is located in the north-western part of India between latitude 278390 to 308550 North and

longitude 748280 to 778370 East, covering a geographical area of 4.4 million ha (Figure 1). For the present study, an

Copyright # 2006 John Wiley & Sons, Ltd. Irrig. and Drain. 55: 491–500 (2006)

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492 K. KUMAR ET AL.

area of 0.35 million ha of the inland alluvium basin comprising Rohtak and Jhajjar districts was chosen (Figure 2).

Topographically the area is a depression, since the topography gently slopes from the north towards the centre

(215m to 200m above mean sea level) and the slope reverses when one moves towards the south and south-west of

the study area. It places restrictions on the gravity outflow of runoff. Groundwater inflow follows almost the same

trend to converge in the study area from all sides, resulting in groundwater rise and deterioration in its quality. As a

result, the whole area is afflicted by problems of surface stagnation of rainwater, waterlogging due to the rise in the

groundwater table and soil salinity.

Figure 1. Location map of the study sites in the state of Haryana (India)


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DRAINAGE REQUIREMENTS AT REGIONAL SCALE 493

In order to assess the long-term groundwater behaviour in the region, an inventory of land and water resources

was prepared. For this purpose, the soil map of the study area was obtained from Chaudhary Charan Singh Haryana

Agricultural University (CCSHAU), Hisar. The area under various textural groups was calculated by digital

planimeter (Table I). Nearly 88% of the area comprises sandy loam and loamy sand soils. The basic infiltration rate,

moisture content of the soils at field capacity and wilting point were taken from data reported by CCSHAU, Hisar

(Phogat, 1999). The initial storage was calculated by the following equation for each of the soil groups:

Initial storage ¼ 0:5�0:33�ðField capacity�Wilting pointÞ (1)

Here the constants 0.5 and 0.33 represent respectively the 50% of the available moisture assumed to be available

for storage and the upper third of the 1m profile where initial storage space would be available.

In order to assess the groundwater regime, relevant data were collected from various state and central agencies,

processed and evaluated as follows.

Figure 2. Base map of a part of the inland drainage basin


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494 K. KUMAR ET AL.

Base maps showing locations of observation wells, exploratory boreholes, block boundaries and headquarters

were collected from the office of the Hydro-geologist, Rohtak (Figure 2). Depth to groundwater level data for all

observation wells located in the study area (pre- and post-monsoon, i.e. June and October 1984–98) were collected

from the Ground Water Cell, Rohtak. The reports prepared by the Haryana State Minor Irrigation and Tubewell

Corporation (HSMITC) in 1984 were referred to for drawing relevant conclusions since these reports make

some remarks on the groundwater regime in 1974–82 (Haryana State Minor Irrigation and Tubewell Corporation,

1984).

Groundwater table contour maps showing the phreatic surface (groundwater table), isobath maps showing depth

to groundwater table, groundwater fluctuation maps at specified time intervals and groundwater quality maps were

drawn. The areas under different groundwater table depth ranges were estimated using a digital planimeter. These

tables and maps were used to calculate the average annual rise in the groundwater table.

Daily rainfall data of seven rain gauge stations, namely Rohtak, Meham, Salhawas, Berikhas, Bahadurgarh,

Jhajjar and Dujana, located in the study area for a period of 24 years were collected from the Irrigation Department,

Rohtak. The Theissen polygon technique was used to assign the effective area to each of the rain gauge stations in

the study area. These seven delineated areas with four soil groups constituted the calculation groups. Frequency

analysis of the rainfall data was conducted using the Weibull (1932) formula. The return periods versus 1–3 days’

consecutive rainfall were plotted and equations representing lines of best fit obtained to determine 1, 2 and 3 days’

consecutive rainfall for 5- and 10-year return periods. Surface drainable surplus was calculated using the following

formula:

Drainable Surplus ¼ ðRainfall� Initial abstractionÞ � NðInfiltrationþ EvaporationÞN

(2)

where N¼ number of days of consecutive rainfall considered in the analysis.

Since the exact value of initial abstraction was unknown, the drainable surplus was calculated for two extreme

cases, i.e. for one case full initial abstraction was assumed while for the other the initial abstraction was assumed to

be zero. The latter represents a case when the groundwater table is quite shallow or the rainstorms occur in

succession without a break. Evaporation during the monsoon season was worked out by averaging the 10-year daily

pan evaporation data for the monsoon season of July, August and September. The average value of 5mm day�1 was

used in Equation (2) to calculate the drainable surplus.

The model, Simulation of Water Flow, Solute Transport and Plant Growth in Soil–Water–Atmosphere–Plant

environment (SWAP), was selected to work out the drainable surplus to halt the rising trend of the groundwater

table. SWAP is an integrated physically based simulation model, for water, solute and heat transport in the

saturated–unsaturated zone in relation to crop growth. For our simulations only the vertical flow of water in the

saturated–unsaturated zonewas considered. Since the objective in using the model was limited, details of the model

are not given here. However, for more details of this model readers may refer to Van dam et al. (1997).

To apply the SWAP model, it was presumed that a subsurface drainage system is provided at a depth of 1.75m

with lateral drain spacing of 75m (Rao et al., 1986; Gupta, 2002). Subsurface drainable surplus was calculated with

this configuration using the SWAP model. All calculations were made on 28 units and cumulative results were

Table I. Infiltration and initial storage available in the soil profile for inland drainage basin

Soil type Area under soiltype (km2)

Basic infiltrationrate (mmh�1)

Field capacity% water (w/w)

Wilting point% water (w/w)

Sand 173 (4.9) 25 12 5Loamy sand 806 (22.8) 2.5 23 6Sandy loam 2313 (65.4) 0.3 27 9Loam and clay 244 (6.9) 0.1 31 11Total 3536

Values in parentheses indicate percentage of the study area.


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obtained by adding the values of individual units. This paper only reports and interprets the cumulative results for

the study area.

RESULTS AND DISCUSSIONS

Groundwater table behaviour

A number of groundwater regime maps (groundwater table contour map, depth to groundwater table map,

groundwater fluctuation map and groundwater quality map) for the pre- and post-monsoon periods were drawn for

the years 1984–98 to assess long-term groundwater table behaviour. The groundwater contour maps revealed that

the groundwater movement was from north-east to north-west and from south-west towards the central part. It

resulted in the accumulation of groundwater in the central portion of the study area. Outflow of the groundwater

was only through a small area in the western direction. Deeper groundwater was generally found in the north-west

direction, whereas the rest of the area is underlain with relatively shallow groundwater levels. The percentage of the

area under less than 3m groundwater table depth continued to fluctuate between 0 and 27% from 1984 to 1994,

except during the monsoon period of 1995 when it suddenly increased to 61% due to heavy rainfall in and outside

the study area. Being a depression, surface runoff from the surrounding areas converged and accumulated in the

study area. It resulted in flooding of large areas. From 1995 onwards, the percentage of the area under this range

fluctuated between 30 and 68%, thereby indicating a shift of a large area under the shallow groundwater regime.

The groundwater levels during June 1984 were deeper than in 1998, although a major shift was seen following

the year 1995. The groundwater fluctuation map for the period (October 1974–October 1998) revealed that during

the last 24 years only 20% of the area experienced an overall decline (0–1m), while the remaining 80% recorded a

rise in groundwater levels (Figure 3). The fluctuation range and the area experiencing this range are shown in

Table II The groundwater levels during the past two and a half decades registered a rise varying from 1 to 19m.

With an average rise of 5m, an average annual rise at the rate of 21 cm was registered during this period.

Considering the problems of surface water congestion and rise in the groundwater table, any strategy to resolve

the problem should be based on an integrated drainage system that should combine a surface and a subsurface

drainage system. Therefore, surface and subsurface drainable surplus were calculated in order to comment upon the

present status of drainage and suggest an amelioration plan.

Surface drainable surplus

One to three days’ daily maximum rainfall revealed that one-day maximum rainfall for a recurrence interval of

5 years varied from 54 to 85mm, while for the 10 years recurrence interval it varied from 79 to 111mm (Table III).

The rainfall increased with increasing duration of rainstorms. The data also revealed that except forMeham, surface

drainage is essentially required to obviate the short-term surface stagnation in cropped lands.

The cumulative weighted average drainable surplus with and without initial abstraction is shown in Table IV. As

anticipated, the drainable surplus increased from 161 to 1254m3 s�1 with no abstraction for the 5-year recurrence

interval (Table IV). On the other hand for the same recurrence interval, the drainable surplus decreased with

increasing duration so much so that for 3 days of storms, the capacity of the drainage network was reduced

drastically and there was no drainable surplus for the 5-year return period when initial abstraction was available.

Similar observations could be made in the case when there is no abstraction although values in this case are

relatively high. The implications of these observations for the study area are as follows:

� Since the groundwater table has been rising over the years, initial abstraction will continue to decrease. As such,

it could be anticipated that the drainable surplus would increase over the years. It would create problems of

handling large volumes of drainable surplus unless steps are initiated to stabilize the groundwater table in the

area;

� In the event of a rising groundwater table, the current capacity of the surface drainage system would not be able

to handle the increased discharge. As such, it would be prudent to explore the possibility of growing crops that


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496 K. KUMAR ET AL.

could tolerate standing water for more than 1 day. Under the present cropping scenario, sorghum and pearl

millet could tolerate water stagnation for 2 days, which seems to be reasonable (Gupta et al., 2004). However, in

future, crops that would be able to tolerate surface stagnation for 3 days would have to be identified in order to

cope with the increasing surplus. Barley could be one such crop provided its marketing could be ensured (Gupta

et al., 2004);

� Although the need for surface drainage could be reduced with management, a part of this would be reflected in

the increased subsurface drainage requirement. Therefore, such a strategy could be adopted only where

subsurface drainage is implemented.

Subsurface drainable surplus

The SWAP model was used to calculate the subsurface drainable surplus for the limited purpose of assessing the

quantum of discharge to prepare a regional management plan. The model was applied without rigorous calibration

Figure 3. Groundwater table fluctuation map of a part of inland drainage basin in Haryana (Oct. 1974–Oct. 1998)


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and validation since the model has been calibrated and validated under almost similar conditions for a shallow

groundwater table situation (Kelleners, 2001). The model was run for a wheat–cotton crop rotation beginning from

the kharif season when the groundwater level was expected to be at its shallowest. The simulations were carried out

for a normal rainfall year (370mm) and once in 10-year rainfall introduced on the 565th day of simulation. The

drainable surplus over the entire simulation period ranged between 0.4 and 1.9mm day�1 (Figure 4). The maximum

drainable surplus was obtained for the monsoon season. To be safe, a drainable surplus of 2mm day�1 could be

taken as the design drainage rate for the subsurface drainage. This design rate matches well with the design

drainage rate advocated by the CSSRI (CSSRI, 2002).

Table II. Percentage area under different groundwater table fluctuationranges (1974–98)

Groundwater tablefluctuation range (m)

% area

<�1 3.6�1 to 0 16.30–1 16.31–3 16.33–5 16.65–7 10.67–9 11.39–11 1.611–13 1.413–15 1.715–17 1.817–19 1.5>19 0.9

Table III. Maximum 1, 2 and 3 days’ rainfall for rain gauge stations for 5- and 10-year return period (mm)

Return period (yr) Days Rainfall

Rohtak Meham Beri Dujana Bahadurgarh Jhajjar Salhawas

5 1 76 54 72 84 82 85 672 110 84 98 105 111 125 843 132 89 107 123 128 141 97

10 1 94 79 88 107 104 111 942 139 137 124 138 149 169 1193 177 144 134 172 167 197 138

Table IV. Total drainable surplus for a part of inland drainage basin

Return period(yr)

Consecutivedays

Drainable surplus withinitial storage (m3 s�1)

Drainable surplus withoutinitial storage (m3 s�)

5 1 161 12542 113 3383 — —

10 1 861 21552 494 8293 50 142


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498 K. KUMAR ET AL.

Surface and subsurface drainage requirement: current status and need

Most of the study area is drained by drain no. 8 which outfalls in the river Yamuna. The area being a depression,

drainage water is also pumped into canal networks or drainage channels to drain micro-level depressions. The total

capacity of the existing surface drainage network was assessed at 170m3 s�1. With the availability of dead storage

in the drainage network, the existing system could handle 1 and 2 days’ consecutive rainfall for a 5-year return

period provided that initial storage was available in the soil profile. However, the discharge from the area could be

more even for a 5-year recurrence interval depending upon the antecedent moisture conditions. Therefore, there is a

need to strengthen the capacity of the surface drainage network in the study area, particularly the on-farm drainage

network without which crops suffer from water stagnation on cropped lands.

The total subsurface drainable surplus for the entire year worked out to be 375mm. Since this dischargewould be

spread over the whole year, it might not pose much of a problem during critical periods. Operational schedules

could be designed to dispose of this surplus at relatively safe periods. However, for the design of a horizontal pipe

drainage system, the maximum value of the drainable surplus, i.e. 2mm day�1, is recommended. In tune with the

studies conducted by the CSSRI, Karnal, 16% of the study area that required immediate provision of a subsurface

drainage system could be designed accordingly. A beginning has been made by the state and an area of 800 ha is

being provided with subsurface drainage in the Beri block of the Jhajjar district for which a drainage coefficient of

2mm day�1 has been assumed in the design. It testifies to the results obtained in this study. If the whole area

needing treatment were put under subsurface drainage, the drainable surplus would be around 13m3 s�1. This

drainable surplus could be disposed of through reuse and through the existing surface drainage network when the

network is running below capacity.

CONCLUSIONS

Regional surface and subsurface drainage requirements have been worked out, suggesting that the area is prone to

surface stagnation and has been facing a serious problem of a rising groundwater table over the last 25 years. The

integrated drainage approach required strengthening of the surface drainage network particularly at farm scale and

implementation of subsurface drainage in at least 16% of the study area. With increasing sensitization, a good

beginning has been made in the region and a drainage project is being implemented to cover 800 ha. This should set

the pace for replication of this treatment in the affected area of the inland drainage basin.

Figure 4. Drainage rates to control water table at optimum depth in the study area


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Gupta SK, Sharma DP, Swarup A. 2004. Relative tolerance of crops to surface water stagnation. Journal of Agricultural Engineering 41: 44–48.

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Documents

Investigations on surface and subsurface drainage requirements at regional scale