Hydrology ofMountainous^4reoi (Proceedings of the Strbské Pleso Workshop, Czechoslovakia, June 1988). IAHS Publ. no. 190, 1990.

Hydrological impact of in the central Himalaya

M. J. HAIGH Geography Unit, Oxford Polytechnic Headington, Oxford, England J. S. RAWAT, H. S. BISHT Department of Geography, Kumaun University , U.P.,

ABSTRACT Deforestation is the most serious environmental problem in , home of the Chipko Movement, the Third World's leading nongovernmental organization (NGO) dedicated to forest con­ servation. This group exists because of the rural people's concern for the loss of forests and their personal experience of the envi­ ronmental consequences. Despite this, it has become fashionable for scientists from some international organizations to argue there is little evidence for recent deforestation, desertification, acce­ lerated erosion and increased flooding in the region. This paper tries to set the record straight. It summarizes results collected by field scientists in Uttarakhand. These data reinforce the popu­ lar view that deforestation and environmental decline are very ser­ ious problems. Preliminary results from the Kumaun University/Ox­ ford Polytechnic instrumented catchment study are appended. This catchment is set in dense Chir (Pinus roxburghii) forest on a steep slope over mica schist in a protected wildlife sanctuary on the ur­ ban fringe at Almora, U.P. The results demonstrate a pattern of sediment flushing associated with the rising flows of the Monsoon.

INTRODUCTION

Deforestation is the most serious environmental problem in Uttar­ akhand, the Himalaya of , India (Fig. 1). This tract, which covers nearly 52 thousand km2 on the western borders of Nepal, is home of the "Chipko" Movement, the Third World's leading NGO devoted to forest conservation (Haigh, 1988a). This group achieved international notice through its successful campaigns to persuade the Indian Government to reform destructive forest poli­ cies and control damaging surface mine operations in the Himalaya, and through its Gandhian approach to development. Chipko exists because of the concern of the rural people, par­ ticularly the rural women, for the loss of their forests and be­ cause of their personal experiences of the environmental consequen­ ces (Jain, 1984). As time goes by, the daily chores of gathering fuelwood and bearing water require longer and longer journeys. As time goes by, obtaining timber to build newly wed children a house, becomes more and more difficult. Worse, each monsoon brings the threat of more severe problems. Bhatt (1980) writes: "In alone there are at least 450 villages where homes, fields 419 M. J. Haigh et al. 420 and forests are crumbling due to the repeated visitations of floods and landslides". The symptoms of environmental degradation every­ where. Despite this, it has become fashionable for scientists from some international organizations to argue that there is little real evi­ dence for accelerated recent deforestation, desertification, ero­ sion, or an increasing flood hazard in the Himalaya (Pearce, 1986; Ramsay, 1987; Hamilton, 1987). These writers tend to stress the variability in ("uncertainties surrounding") the data which is pro­ duced by researchers in the Himalaya (Ives, 1987; Thompson & War- burton, 1985). They base their own generalisations on studies in the Middle Hills of Nepal. The Kathmandu area has one of the long­ est histories of development in the Himalaya and one which con­ trasts very sharply with the much larger tracts of the Himalaya where development has become a problem during the last century. These writers also tend to base their hydrological observations exclusively on the publications of foreign workers in Nepal, which has yet to establish a major hydrological station. Writings from India, Pakistan, and even other mountain areas tend to be ignored. There are, of course, very good reasons why friends of Nepal might not wish that nation to be linked to flooding and sediment pollution problems which extend beyond its boundaries (Chalise, 1986). However one may sympathise with that wish, the scientific evidence is different. Further, it is critical to the well being of neighbouring nations, with large mountain areas of their own, to be aware of the problems which exist in their own hill country and to channel their resources towards the solution of those problems. This paper attempts to set the record straight. It is a summary of the results collected by research workers in Uttarakhand, India. These results tend to support the disturbing images of environment­ al degradation put forward by most NGOs and independent environmen­ tal researchers of the Himalayan region. The paper also includes a note on the first data from the first hydrological monitoring sta­ tion in the Central Himalaya, which has been established by Kumaun University and Oxford Polytechnic at Almora.

THE ENVIRONMENTALIST'S MODEL OF ENVIRONMENTAL DECLINE IN THE HIMALAYA

Originally, the Himalaya of Uttarakhand were largely mantled with trees. However, the expansion of population during the British period caused the forests to become stressed by the needs of the subsistence economy. British attempts to conserve the forest re­ sources through closure resulted in a massive increase in pressure on those forest lands left in local control, forest destruction through political protest, and the alienation of local people from any feeling of responsibility for the forest resource (Pant, 1922). Military demands during two world wars, the growing timber and fuelwood demands, and tree theft (which may account for 25% of all timber exploitation in the hills) all added to the degradation of the forests. To this has been added the growth of the road network which has both directly and indirectly contributed to forest dest­ ruction through clearance, landsliding and facilitating tree theft 421 Hydrological impact of deforestation

78 80 82 84

Fig. 1 The Uttar Pradesh Hill Region. 1) Uttarkarshi, 2) Dehra Dun, 3) Tehri, 4) Chamoli, 5) , 6) , 7) Almora, 8) .

(Haigh et al., 1987; Haigh 1983, 1984). Meanwhile, the population of just 4.787 million (1981) continues to expand at a rate of around 2.3% p.a. In its wake, agricultural extension proceeds at about 1.5% p.a. and livestock at about 0.18 cattle units p.a. (Shah, 1982). So, over the years, the tree cover has become depleted. Once, the tree canopy, the undergrowth and particularly the leaf litter, intercepted the bulk of the incident rainfall which dripped and seeped slowly to a deep, open structured soil with a large and well developed biota. Little remained at the soil surface to cause sur­ face runoff. However, a proportion of the water which infiltrated was trapped by the vegetation and returned to the atmosphere as évapotranspiration. The remainder soaked to the groundwater to feed springs, seeps, and to provide the base flow of perennial streams. Then, during the last century, and especially during the last few decades, the mountains suffered severe forest degradation, much of which was due to processes with origins outside the mountains themselves: colonial, commercial and national, some of which was due to pressures building up in local communities. The forest cov­ er of the hills was reduced precipitously and that which remained suffered thinning due to lopping for timber. Overgrazing and burn­ ing to improve pasture prevented regeneration. Now, there remained much less vegetation to protect the soil. The soil became more vulnerable to erosion and more easily compac- M. J. Haigh et al. Ail

i U T3 > CO CM Q) C O o o d > tt! rH d d O i-H tu

C c o O -H -O -H 4-1 C -t-1 Dux) m co CM Cs) 3 m o) c m co r- m o « u u M 0) U O) *-> > C CM CM ON •* CM CO (-- r- 00 ON O ON a. •H C

o o 00 ON n r- m 00 00 .-H a. CM aoi

I co ON ON s > d d d d d d (U O *-> r-\ VI <4-l

I bo m D O iH •o- i-H CM O CM M rH r- ON 00 00 00 00 xï td E-l <4-l

I •* ON m ~fr O C0 G 00 r-. t-H VO •* m e CM t-H ON CO CM <-H e

a. o O co 00 t-< co ON c s^ ON 00 ON 00 (13 co r» U

0» d m (8 ni as O o 00 + (0 X) 01 ai Q) ai ai u c C o x x o

ted. The reduced vegetation cover allowed more water to reach the soil more rapidly and returned less to the atmosphere. Surface runoff began to occur more frequently and, as it did so, rates of erosion began to rise. Erosion rapidly reduced the depth of the soil and thus its capacity to store water. As time passed, more and more water ran across the ground surface, and less and less soaked into the ground. As a result, the groundwater table became lowered, springs ran dry and the landsurface suffered desertifica­ tion. As the tree roots in the soil rotted away, the steep hill­ sides became prone to an increased frequency of landsliding. Soil mobilised by erosion and rubble from landslides was dumped in streams and river channels causing their beds to aggrade rapidly. Perennial streams became buried beneath channel debris. Perennial streams became ephemeral due to the decline in the water table and reduction in base flow. Flooding became more serious because of the increased volume of water in the environment, because of the increased frequency and volume of surface runoff and because of the rising levels of affec­ ted river beds. Landsliding became more frequent because of the toe erosion caused by the increased monsoon floods, because of deforestation and because of road construction. Inevitably, part of the problem of increased sediment loads and higher flood peaks was passed downstream to affect areas hundreds of miles from the deforested headwaters. For example, the Alaknanda flood of 1970 left 2 m deep deposits of debris at Srinagar (Garhwal), 100 km from the flood source and blocked a 10 km reach of the Ganga Canal near Hardwar 300 km from the flood's source (Bhatt, 1980). Essentially similar versions of this model have received widespread and regular publication (e.g. Uttarakhand Seva Nidhi, 1986; Haigh, 1984; Myers, 1984, 1986; Ashish, 1979).

EVIDENCE FROM UTTARAKHAND

Deforestation and forest degradation

Official statistics suggest that the forest cover of Uttarakhand is about 67 %. However, despite an active program of planting, even the area of forest under the control of the Uttar Pradesh Forest Department seems to have declined by 5 X in the period 1965 - 1980 (Kumar, 1981). Gupta (1979) attempted to use satellite imagery to quantify actual forest cover and suggested that just 37.5 X of the area is currently forested. Tiwari et al. (1986) found that about 29 X of Uttarakhand was forested but that 'good forest', with a crown canopy greater than 60 X, accounted for only 4.4 X of the land. Tiwari & Singh (1987) surveyed 200,000 ha in Naintal and Almora Districts using aerial photographs in support of field data. Some 45 X of this area is not forested, 23 X being given over to agri­ culture, 15 X to scrub or grassland. Just 2 % of the area is clas­ sed as wasteland due to erosion but 85 X of the agricultural land suffers erosion problems. The rate of agricultural extension into forest land is 1.5 X p.a. Fifty-five percent of the area is classed as forest, but only 6 X of this woodland has a crown canopy which exceeds 60 X, whilst 21 X has a crown canopy of less than M. J. Haigh et al. 424

40 % which indicates widespread forest thinning and degradation.

Rainfall interception and runoff

During the monsoon seasons of 1981 and 1982, Pathak et al. (1985) undertook studies of rainfall interception at six forest sites in Uttarakhand. Five of these sites had a canopy cover in excess of 70 X and only one as low as 38 X. Throughfall rates ranged from 75 to 92 % and canopy interception from 8 to 25 X. Workers at Dehra Dun in the foothills have reported that pine forest (1,156 trees /ha) is capable of intercepting 22 X of incident rainfall (Dabral et al., 1986), whilst densely coppiced Sal may intercept as much as 34 X (Ghosh & Subba Rao, 1979). Pathak et al. (1985) found that stemflow accounted for less than 1 % of the total rainfall (0.3 - 0.9 %). Dabral et al. (1968), however, considered that stemflow in Himalayan pine could reach 4 X of the rainfall, and 6 to 9 % in broadleaved forest (Ghosh & Subba Rao, 1979). At the ground surface, the litter layer intercepted some 7 to 10 X of the total rainfall (Pathak et al., 1985). Ghosh & Rao (1979) estimate litter interception as 5 % whilst Dabral et al. (1968) measured 7.6 % beneath pine (P. roxburghii), 9 X beneath Sal and 8.9 % beneath teak (Tectona grandis). Most of the remaining rainfall is intercepted by the undergrowth or goes to infiltration (59 - 84 %; see Pathak et al., 1985). Sur­ face runoff did not develop for showers of less than 10 mm. Meij- erink (1974) confirms that runoff events are rare and that much of the sediment which is mobilised is trapped on man-made or forested river terraces where the infiltration capacity is high. He observ­ ed near that the runoff generated by a 0.4 km2 catchment would disappear on a terrace fringe of 200 to 300 m. At Bhaintan, on the -Tehri road, Mohan & Gupta (1983) measured infil­ tration rates under different land uses. Stable infiltration rates beneath thin forest averaged 12.5 mm/hour (range 3.5 to 20.0 mm/ hour: 4 test sites). On terraced crop land, the average was 33.6 mm/hour (range: 8.0 - 41.5 mm/hour: 5 test sites) whilst one test on grassland gave a final infiltration rate of 21.5 mm/hour. It is widely accepted that well maintained back-sloping terraces are best practice in the region for agricultural soil and water conserva­ tion. (Poorly maintained terraces, unfortunately, are a different matter, and terrace abandonment and breakdown is a growing problem in Uttarakhand). Mohan & Gupta (1983) relate the poor infiltration capacity of their forest to compacted soils and poor litter capac­ ity and their results contrast sharply with those of Ghosh & Rao (1979). These workers compared infiltration rates beneath Sal for­ est and on neighbouring agricultural fields. The stable infiltra­ tion rate beneath dense, well developed Sal plantation, 38 mm/hr, was twice that on neighbouring, unterraced agricultural lands. In forest, very little of the incident rainfall remains to gen­ erate surface wash on the hillslopes. Pathak et al. (1985) meas­ ured surface runoff as 0.2 to 1.3 X on their dense forest, 25 m2 plots (Table 1). Overland flows were conspicuously higher from the site with the least forest cover (1.3 % vs 0.8 - 0.2 %). These data lead this team to postulate that subsurface soil flows were 425 Hydrological impact of deforestation major pathways for soil loss (Singh et al., 1983). However, The Pathak team results do contrast with those reported from the Murree Hills, Pakistan. Here, a team from the Pakistan Forest Institute measured runoff on a 45° slope covered by a deep (1.5 m) Typic Hap- ludoll developed underneath Chir Pine (Raeder-Roitzsch & Masrur, 1969; Choudhri & Nizami, 1985). The Pakistani team employed 4 m2 runoff plots and found that while forested plots yielded only 4 X of the rainfall as runoff, dense grass and young trees gave 17 to 18 X, thin grass 28 to 38 X, and bare soil 47 X. Runoff jumped from 4 to 11 % in the twelve months after tree harvesting (Masrur & Hanif, 1972).

Desertification and floods

Seth & Khan (1960) have indicated' that the moist broadleaved for­ ests of the Lesser Himalaya may return as much as 50 X of the inci­ dent rainfall back to the atmosphere through évapotranspiration. Pot studies suggest that Chir Pine has a lower transpiration rate than the local broadleaves but that it consumes more water than either Sal or the Oaks which Chir is tending to replace on many Uttarakhand hillsides (Raturi & Dabral, 1986). In Japan, it was discovered that on losing a 69 % pine cover to nematode infection, the water yield of one 69 ha catchment increased by 110 mm. Base flows were 50 to 100 X greater at different seasons of the year and the reason was the reduction in évapotranspiration following the death of the trees (Abe & Tani, 1985). By contrast, when Eucalypts were planted in a denuded watershed in the same area, total runoff was reduced by 28 X (Mathur et al., 1976). Preliminary results from the Fazegut hydrological station in Swat, Pakistan, on what is currently badly degraded and overgrazed grassland (63 - 78 X exposed rock) show that, of a 57 to 61 mm rainfall event, 49 to 58 X was converted to runoff, and of a 19.5 to 21.4 mm event, 5 to 23 X was converted to runoff (P.F.I. 1987 - unpublished data). In Uttarakhand, it has been reported, that on a 4.6 ° slope of silt clay loam, natural grass covers contribute 21 X of the rainfall as runoff whilst compacted, bare fallows, return 71 X (Dhruva Narayna, 1987). Mishra et al. (1979) relate runoff to the leaf area of the vegetation. Studies in the Siwalik foothills, from a 24.2 ° sloping grassed watershed, indicated that as the grass yield increased from 65 to 85 q/ha so runoff decreased from 38 to 31 X of the incident rainfall (Agnihotri et al-, 1985). In sum, less vegetation means more runoff. Nevertheless, it is an oft repeated, if less easily substantiat­ ed complaint of the hill's people, that streams are drying up as a result of forest degradation. However, there is more than anecdot­ al evidence for this phenomenon, which appears to be caused by dramatic changes in the infiltration and water storage capacity of the soils in areas which have suffered forest degradation. Almora Town, the traditional capital of Kumaun, eastern Uttar­ akhand, straddles a ridge with steep sloping sides. Since 1560 its demand for timber and fuel has stripped away local forest cover. The area once possessed some 360 springs, many are enshrined in local place names, but today, less than 10 X still function (Joshi et al., 1983). A survey of springs in the catchment in M. J. Haigh et al. 426

Nainital District found that 45 X have gone dry in recent memory (Bartarya, 1988; Valdiya, 1985; Moddie, 1985). In Uttarakhand as a whole, 55 X of the springs are said to have dried up during the last 20 years while the number of villages suffering water scarcity may have increased by 40 X in the last 13 years (Uttarakhand Seva Nidhi, 1986). Detailed studies of channel capacities and sediment load are be­ ing undertaken by J.S. Rawat in the Nana Kosi Basin of Kumaun (Rawat & Bisht, 1986). Early returns from the Jamthara Gadh catch­ ment indicate that streams are much reduced in deforested subcatch- ments (Rawat, 1987). The base flow in the Gaula river may have decreased by a third in the last decade (Bartarya, 1988; Valdiya, 1985). A Sal forest watershed near Dehra Dun in the foothills of Garh- wal, western Uttarakhand, was cleared for agriculture as part of a paired catchment study. The volume of runoff increased by 15 X and the peak rate of runoff by 72 X compared to an undisturbed catch­ ment (Sastry et al., 1986). Another Sal forest site involving paired 6 ha catchments on a 20 to 30° slope was employed for an ex­ amination of the effects of thinning. One tree in five was removed (Subba Rao et al., 1985). This treatment did not affect the volume of flow but flood peaks increased (8.6 X) in the thinned catchment, especially during more intense rainstorms in the first year after cutting when canopy interception was reduced from 18 to 13 % (Megahan, 1988). Planting Eucalypts in a degraded catchment, also near Dehra Dun, reduced discharge by 28 Z and the peak flow by 73 X (Mathur et al-, 1976). Isolated from the emotive issues of Indo-Nepali politics, most researchers agree that a reduction in the forest cover tends to lead to an increase in flood peaks and in runoff, especially if this is accompanied by substantial reductions in infiltration. Quite obviously, the waters formerly lost to évapotranspiration have to go somewhere and if this is not into the ground, and not into the base flow of the major rivers, then other options are limited. The land area considered by India to be flood prone has doubled in the 10 years to 1989, from 20 to 40 million ha (Govern­ ment of India, 1980).

Sediment production and channel response

In 1978, the Mussoorie Bypass was built across a partially defores­ ted hillside. The new road blocked four parallel, ephemeral, stream channels draining similar, 1 km2 catchments on a 40 ° slope. Two channels drained protected forest and two drained deforested scrubland. The monsoon turned the unfinished road into an effic­ ient bedload sediment trap. Some 50 m3 of sediment was trapped be­ neath each forested catchment compared to 230 and 370 m3 beneath the deforested, grassland and scrub, catchments (Haigh, 1982). Singh, Pandey and Pathak (Singh et al., 1983; Pandey et al., 1984) have compared runoff and sediment yield from forested and de­ forested catchments in Kumaun using 25 m3 runoff plots. Pandey ejt al. (1983) calculate soil losses due to surface runoff and suffo- sion as 3.2 t/km2 and 6.2 t/km2 from oak forest and non-forest sites respectively (Table 2). The use of 25 m2 runoff plots for 427 Hydrological impact of deforestation

this study, of course, eliminates runoff generated upslope, sediment contributions due to channelled flows, to mass movement, and to human interference, notably through construction and road clearance. Consequently, the runoff and soil losses indicated tend to be on the low side (Table 2 but cf Masrur & Hanif, 1972). Hill roads are the cause of many landslides and rate as major sources of sediment. Estimates of the rates of sediment production by roadways in the Central Himalaya run from 430 to 550 m3/km of roadway/year (Patnaik, 1978; Valdiya, pers. comm). However, the results of detailed case studies suggest that these figures may be an underestimate (Bansal & Mathur, 1976; Haigh, 1988b). Landslides, however, are more widespread, and according to popu­ lar belief, their frequency is increasing rapidly (Bhatt, 1980; Bahuguna, 1982). Despite this Meijerink (1974), working in the Aglar valley of Garhwal, calculates that superficial debris slides generate only 0.5 t/km2/year of debris of which a fifth reaches the river channel. He also calculates that the catchment's long term, geological sediment yield is 9 to 45 t/km2/year. By contrast, soil losses as high as 15600 t/km2/year have been measured on 4.6 ° slope tilled fallow in the Dehra Dun area. Dhruva Narayana (1987) estimates the sediment yield of the Tehri 's catchment as 1940 t/km2/year. The sediment loads carried by Himalayan rivers can be very high. Das (1987) sampled the sediment loads of the Bhagirathi and Bhilangana rivers above the High dam in Garhwal. Between July and October, these rivers carry a silt load of the order of 2 kg/m3 and 44 kg/m3, respectively.

Table 2 Overland Flow and Runoff during Monsoon Season in Central Himalayan Forests (Pandey et al., 1983)

Sites Tree Density Ground Cover Overland Flow Soil Loss stems/ha X X of rainfall t/km2

Forest (Quercus spp) 148 47 0.44 2.5 Forest 116 41 0.49 3.7 Forest 78 38 0.44 2.6 Forest 33 19 0.45 4.0 Road Debris Deposit 0 12 0.60 8.1 Landslide (21 yrs) 0 31 0.45 4.2 Landslide (13 yrs) 0 18 0.60 6.2 Cropland (maize) 0 46 0.57 6.4

Many channels in the area raise their beds by up to 10 cm a year (Bahunga, 1978). Sediment-choked channels are not uncommon in the hills, especially in areas close to construction activity. The sediment is supplied by deforestation, road construction and clear­ ance, and by landslides which are often due to the channel itself. A survey of a kilometer reach of second order channel in a defores­ ted area below Mussoorie in 1978 discovered 9 fresh landslides of more than 20 m3 contributing more than 1,000 m3 to the channel bed. M. J. Haigh ei al. 428

However, the most spectacular illustration of this process is to be found at Raj pur near Dehra Dun. Here, in 1919, the Kaulagarh Bridge was built across a small perennial stream. The bridge sof­ fit cleared the bed of the perennial rock floored stream by 19.5 m. However, just upstream, deforestation triggered landsliding which dumped an enormous volume of sediment in the channel. In 1979, the bridge cleared a wide boulder run by just 1 m (Photographs in Haigh, 1984; Nossin, 1971).

HYDROLOGY OF HIMALAYAN PINE FOREST: PRELIMINARY RESULTS

The first hydrological monitoring station in Kumaun commenced oper­ ation in March 1987. The project, founded as a research collabora­ tion between Oxford Polytechnic and Kumaun University, is establi­ shed at Almora, in the heart of the lesser Himalaya (altitude: 1,615 m). The ultimate aim is to compare the hydrological behav­ iour of forested and deforested hillsides. However, to date, only one (the control) catchment is producing data. The control catchment is the Animal Park Watershed, which drains a nature preserve on the outskirts of Almora. This preserve is securely fenced and policed by forest guards to prevent incursion. The Park is a rare example of undisturbed pine forest in the Almora area. The tree canopy is 82 % and ground cover by vegetation and litter exceeds 75 X. The gauged stream drains a small (area: 1.1 km2) elongated (1.9 km) catchment developed on the upper convexity of a steep hillside (channel slope > 25°). The catchment is underlain by im­ permeable mica schist, perhaps with some interbedded quartzites. These strata belong to the Almora Crystalline group. Instrumentation consists of a v-notch weir, established accord­ ing to British Standard specifications, with a stilling pond pro­ tected by an efficient sediment trap. A Hindustan Clockworks chart recording stage recorder is set in the stilling pond adjacent to the weir. A recording rainguage has been established nearby and these records are calibrated against data collected at the Viveka- nanda Laboratory for Hill Agriculture of the Indian Council of Ag­ ricultural Research some kilometres distant. Runoff records are supported by a weekly program of sampling of suspended sediment and dissolved loads. During the first 8 months of record, from April 17th, 1987 to January 1st, 1988, the catchment received 488.3 mm of precipitation of which 80 X fell in the monsoon season of July to September. Discharges during this period ranged from a low of 0.09 1/s on June 6th to a high of 38 1/s on August 12, 1987. Suspended sediment concentrations ranged from 0 mg/1 during May and November-December to a peak of 870 mg/1 near the close of the Monsoon in early Sept­ ember. Dissolved loads proved much less variable and were, on average, of greater dimension (Durgin, 1984). The peak concentra­ tion was 428 mg/1 recorded in early September while the lowest concentrations, 80 to 40 mg/1, were measured in samples collected in October through December. Preliminary analysis of the data suggests that there is an annu­ al cycle of sediment release controlled by successive phases of 429 Hydwlogical impact of deforestation discharge. High suspended sediment loads are associated with each new sustained peak discharge. Subsequent repetition of the same discharge tends to be associated with lower suspended sediment loads. Indeed, suspended sediment loads decline to zero in the stable flow conditions at the close of the monsoon.

Table 3 Discharge recession at the close of the monsoon season of 1987: Animal Park Pine Forest Watershed, Almora, U.P.

Discharge Date Time 1/s day/month hours of the day

3.02 19/10 17/18 2.15 19/10 18/19 1.12 19/10 19/20 0.99 19/10 20/21 0.95 30/10 12/13 0.90 30/10 16/17 0.85 1/11 13/14 0.80 2/11 16/17 0.75 3/11 15/16 0.70 4/11 15/16 0.60 4/11 16/17 0.55 12/11 24/01 0.50 21/11 11/12 0.45 25/11 16/17 0.45 10/12 24/01

The pattern suggests that, during the autumn, and especially during the dry hot summer months, mobilisable sediments accumulate in the catchment and in the stream channel. With the onset of the monsoon, these sediments are progressively flushed out by the se­ quentially rising discharges. The character of this process, how­ ever, requires further and more detailed investigation. Hydrographs of individual rainfall events based on hourly data indicate that catchment response to rainfall is rapid. The flow peak is achieved in the hour following the onset of the storm. For example, on 23/4/1987 a three-hour storm deposited 2.0 + 1.0 + 3.5 = 6.5 mm. Before the storm, the flow was 0.61 1/s, this rose to 0.69 1/s in the second hour of the storm and fell back to 0.62 1/s in the hour following the storm, after which there was a long slow decline in flow rates which stabilised as 0.613 1/s 9 hours later. The last rainfall of the monsoon season fell on the 19/10/1987. This storm deposited 8 + 2 = 10 mm in two hours. Discharge rose from 0-9 to 3.0 1/s in the first hour of the storm. Two hours later, discharge was down to 1.1 1/s, and stabilised at 1.0 1/s some 23 hours after the peak was achieved. Further recession proceeded slowly (Table 3), though not especially evenly. Abrupt drops in discharge were recorded on October 30th and again on the 4th of November. However, whether these are real, or due to faults in data collection, is not yet determined. If real, these features may relate to thresholds of exhaustion in certain categories of M. J. Haigh et al. 430 catchment storage. It is, of course, no coincidence that most flow mimima are achieved in late afternoon when both evaporation and transpiration rates are highest.

CONCLUSION

The causes and consequences of environmental degradation in Uttar- akhand's Central Himalaya are common knowledge to local residents who have seen their environment change through their lifetime. Their observations are reinforced by the various and scattered sci­ entific investigations which have been undertaken in the region. In Uttarakhand, the nature of the problems are beyond dispute. No longer are such matters considered the most appropriate topics for investigation. Instead, attention is now focused on remedial measures and upon environmental regeneration in the Himalaya (Singh, 1985). The focal problem here, however, runs beyond the scope of this paper. It concerns a restructuring of the social, economic, and agroecosysterns of Uttarakhand (Ashish, 1978; Singh et al., 1984). It concerns rural uplift and ecodevelopment (Uttarakhand Seva Nidhi, 1986; Haigh, 1988a).

REFERENCES

Abe T., & Tani, T. (1985) Streamflow changes after killing of pine trees by the pinewood nematode. J. Japan. Forest. Soc, 67 (7), 261-270 (English abstract) Agnihotri, Y., Dubey, L.N., & Dayal, S.K.N. (1985) Effect of vegetation cover on runoff from a watershed in Shivalik foothills. Ind. J. Soil Conserv., 13 (1), 10-13 Ashish, M. (1979) Agricultural economy of Kumaun Hills: threat of ecological disaster. Economic and Political Weekly, 14 (25), 1058-1064 Bahuguna, S.L. (1982) World About Us: Axing of the . British Broadcasting Company: Education & Training Video (EP 1/AEER00BY/161450) 60 min. Bartarya, S.B. (1988) Geohydrological studies of the Gaula Catchment. Kumaun University, Department of Geology, Nainital, U.P., Ph.D. thesis (cited in: Current Science, 58 (8), 1989, 417-426) Bhatt, C.P. (1980) Ecosystem of the Central Himalayas and Chipko Movement. Dashauli Gram Swarajya Sangh, Gopeshwar, U.P. Chalise, R.S. (1986) Constraints of resources and development in the mountainous region of South Asia. In: Joshi, S.C., Haigh, M.J., Pangtey, Y.P.S., Joshi, D.R. and Dani, D.D. (eds): Nepal Himalaya: Geoecological Perspectives. H.R. Publishers, Nainital, 12-26 Choudhri, T.H. & Nizami, M.I. (1985) Murree Series. In: Ahmad, M. Akram, M. Shabir Baig, M., Yasin Javed, M. and Riaz-ul-Amin (eds): Proceedings of the 12th International Forum on Soil Taxonomy and Agrotechnology Transfer, Pakistan, Vol. 2: Field Excursions. Soil Survey of Pakistan and Soil Management Support Services USA, Lahore, 1986, 208-216 431 Hydrological impact of deforestation

Dabral, B.G., Prem Nath, & Swarup, R. (1963) Some preliminary investigations on rainfall interception by leaf litter. Indian Forester, 89 (2), 112-116 Dabral, B.G. & Subba Rao, B.K. (1968), Interception studies in Chir and teak plantations - New Forest. Indian Forester, 94, 540-551 Das, S.M. (1987) and upper Ganga silt pollution. Himalaya: Man and Nature, 10 (9), 49-51,54 Dhruva Narayana, V.V. (1987) Downstream impacts of soil conservation in the Himalayan region. Mountain Research and Development, 7 (3), 256-263 Durgin, P. (1984) Subsurface drainage erodes forested granitic terrain. Physical Geography, 5 (1), 24-39 Ghosh, R.C. & Subba Rao, B.K. (1979) Forest and floods. Indian Forester, 105 (4), 249-259 Ghosh, R.C, Subba Rao, B.K. & Ramola, B.C. (1980) Interception studies in Sal (Shorea robusta) coppice forest. Indian Forester, 106 (8), 513-514 (1980) Report of the National Commission on Floods, Department of Irrigation, New Gupta, P.N. (1979) Afforestation, Integrated Watershed Management, Torrent Control and Land Use Development for U.P. Himalayas & Sivaliks. Uttar Pradesh Forest Department, Lucknow Haigh, M.J. (1988a) Understanding "Chipko", the Himalayan peoples movement for forest conservation. Internat. J. Environ. Studies 31, 99-110 Haigh, M.J. (1988b) Dynamic systems aproaches to landslide hazard research. Zeitschrift fur Géomorphologie N.F. S-b 67, 79-91 Haigh, M.J. (1984) Deforestation and disaster in northern India. Laud Use Policy, 1 (3), 187-198 Haigh, M.J. (1982) A comparison of sediment accumulations beneath forrested and deforested microcatchments, . Himalayan Research and Development, 1 (2), 118-120 Hamilton, L.S. (1987) What are the impacts of Himalayan deforestation on the -Brahamaputra lowlands and delta? Assumptions and facts. Mountain Research and Development, 7 (3> , 256-263 Ives, J. (1987) The Himalaya - Ganges problem - the theory of Himalayan environmental degradation: its validity and application challenged by recent research. Mountain Research and Development, 7 (3), 181-183, 189-199 Jain, S. (1984) Women and peoples ecological movement: A case stiidy of women's role in the Chipko movement in Uttar Pradesh. Economic and Political Weekly, 19 (41), 1788-1794 Joshi, S.C., Joshi, D.R. & Dani, D.D. (1983) Kumaun Himalaya: Geographical Perspectives on Resource Development. Gyanodaya Prakashan, Nainital Kumar, V. (1981) Trends and economic analysis of U.P. Hill forests. G.B. Pant University of Agriculture and Technology, Pantnagar, U.P., Ph.D. thesis (cited in: Journal of Rural Development, 2 (1> , 1983, 134-137) Masrur-, A. & Hanif, M. (1972) A study of surface runoff and sectiment release in a Chir pine area. Pakistan J. Forest., 22 (2>, 113-142 M. J. Haigh et al. 432

Mathur, H.N., Ram Babu, Joshie, P., & Singh, B. (1976) Effect of clearfelling and reforestation on runoff and peak flow in small watersheds. Indian Forester, 102 (4), 219-226 Mathur, H.N. & Sajwan, S.S. (1978) Vegetation characteristics and their effect on runoff and peak rates for small watersheds. Indian Forester, 104 (6), 398-406 Megahan, W.F. (1988) Effects of forest roads on watershed function in mountainous areas. In: Balasubramanian, A.S., Chandra, S., Bergado, D.T. & Prinya Nutalya (eds): Environmental Geotechnics and Problematic Soils and Rocks, Balkema, Rotterdam, 335-348 Meijerink, A.M.J. (1974) Photo-hydrological Reconnaissance Surveys. Vrije Universiteit te Amsterdam, Academische Proefschrift Mishra, P.R., Sud, A.D., Madan Lai & Kehar Singh (1979) Central Soil and Water Conservation Research and Training Institute (Dehra Dun), Annual Report, 99 (cited in Agnihotri et al., 1985) Moddie, A.D. (1985) Development with desertification: U.P. hills Bhimtal's water system: facts, policies, lacuna and responses. Central Himalayan Environment Association, Bulletin 2, 26-36 Mohan, S.C. & Gupta, R.K. (1983) Infiltration rates in various land uses from a Himalayan watershed in Tehri Garhwal. Ind. J. Soil Conserv. 11 (2/3), 1-4 Myers, N. (1986) Environmental repercussions of deforestation in the Himalayas. J. World Forestry Resource Management, 2, 63-72 Nossin, J.J. (1971) Outline of the geomprphology of the , northern U.P., India. Zeitschrift fiir Géomorphologie N.F., 12, 18-50 Pandey, A.N., Pathak, P.C., & Singh, J.S. (1983) Water, sediment and nutrient movement in forested and non-forested catchments in Kumaun Himalaya. Forest Ecology and Management, 7 (1), 19-29 Pant, G.B. (1922) Forest Problem in Kumaun. Gyanodaya Prakashan, Nainital (1985) Pathak, P.C., Pandey, A.N., & Singh, J.S. (1985) Apportionment of rainfall in Central Himalayan forests (India). J. Hydrol., 76, 319-332 Pathak, P.C., Pandey, A.N., & Singh, J.S. (1984) Overland flow, sediment output and nutrient loss from certain forested sites in central Himalaya, India. J. Hydrol., 71, 239-251 Patnaik, N. (1981) Role of soil conservation and afforestation for flood moderation. International Conference on Flood Disasters, I.N.S.A., New Delhi, circulated mimeo Pearce, A.J. (1986) Erosion and sedimentation. East-West Center, Environment and Policy Institute, Hawaii, U.S.A., Working Paper Raeder-Roitzsch, J.E. & Masrur, A. (1969) Some hydrologie relationships of natural vegetation in the Chir pine belt of West Pakistan. Pakistan J. Forest. 19 (1), 81-98 Ramsay, W.J.H. (1987) Deforestation and erosion in the Himalaya - is the link myth or reality? IAHS Publication 167, 239-250 Raturi, A.S. & Dabral, B.G. (1986) Water consumption by Chir Pine (Pinus roxburghii), Banj-0ak (Quercus incana), Sal (Shorea robusta) and Ipil-ipil (Leucaena leucocephala) in juvenile stage. Indian Forester, 112, 711-733 Rawat, J.S. (1987) Modelling of water and sediment budget: concepts and strategies. Catena, Suppl. 10, 147-159 433 Hydrological impact of deforestation

Rawat, J.S. & Bisht, H.S. (1986) Channel network capacity and geochemical properties of water of the Nana Kosi Basin: Kumaun Lesser Himalaya, India. Department of Geography, Kumaun University, Campus Almora Sastry, G., & Dhruva Narayan, V.V. (1986) Hydrologie responses of small watersheds to different land uses in Doon Valley. Ind. J. Agricult. Sci., 56 (3), 194-197 Seth, S.K. & Khan, M. (1960) An analysis of the soil moisture regime in sal (Shorea robusta) forest of Dehra Dun with reference to natural regeneration. Indian Forester, 86 (6) Shah, S.L. (1982) Socioeconomic, Technological, Organisational and Institutional Constraints in the Afforestation of Civil, Soyam, Usar and Waste Lands for Resolving the Fuel Wood Crisis in the Hill Districts of Uttar Pradesh. Vivekananda Laboratory for Hill Agriculture, Indian Council of Agricultural Research, Almora, U.P. Shah, S.L. (1982) Ecological degradation and future of agriculture in the Himalayas. Ind. J. Agricult. Econ. 37 (1), 1-22 Sheik, M.I. & Hafeez, M. (1975) Forests and forestry in Pakistan. Pakistan Forest Institute, Peshawar Singh, J.S. (ed), (1986) Environmental Regeneration in the Himalaya. Central Himalayan Environment Association and Gyanodaya Prakashan, Naintal Singh, J.S., Pandey, U. & Tiwari, A.K. (1984) Man and forest: a Central Himalayan case study. Ambio, 13 (2), 80-87 Subba Rao, B.K., Ramola, R.C. & Sharda, V.N. (1985) Hydrologie response of a forested mountain watershed to thinning: a case study. Indian Forester, 111, 418-431 Thompson, M. & Warburton, M. (1985) Uncertainty on a Himalayan scale. Mountain Research and Development, 5 (2), 115-135 Tiwari, A.K., Saxena, A.K. & Singh, J.S. (1986) Inventory of forest biomass for Indian Central Himalaya. In: Singh, J.S. (ed): Environmental Regeneration in Himalaya. Central Himalayan Environment Association & Gyanodaya Prakashan, Nainital, 236-247 Tiwari, A.K. & Singh, J.S. (1987) Analysis of forest landuse and vegetation in a part of the Central Himalaya using aerial photographs. Environmental Conservation, 14 (3), 233-244 Uttarakhand Seva Nidhi (1986) Workshop on the Seventy Five Year Plan for the Kumaun Hills. Consul Printers, Nainital, U.P. Valdiya, K.S. (1985) Himalayan tragedy: big , seismicity, erosion and drying up of springs. Central Himalayan Environment Association Bulletin 1, 1-24