LANDSLIDE

Introduction:
The Himalayas are in a highly deteriorate state due to intensive deforestation, large scale road construction, mining and cultivation. About 25% of the geographical area of our country is hilly terrain and therefore, appropriate control measures are immediately warranted.

In the Himalayan terrain, landslides and soil erosion decidedly are serious problems because of steep slopes, cut-off topography, geological sandstone formation, sandy-loam soil and other climate factors. Soil and water are the basic resources of the Himalayan region and they must be conserved carefully to check ecological imbalance. Preliminary analysis shows that above 240 cubic metres of soil are conveyed every year by the Himalayan rivers. It is estimated that about 51,00,000 m/tons of valuable nutrients with soil are washed down annually, which in money terms, will amount to Rs. 7000 million per year. This hazard has to be stopped and it is only possible we treat all such areas with permanent remedies. Treatment with biological methods is one such and has three major impacts.

It conserves soil
It conserves water and
provides permanent relief to the land

Increasing number of landslides due to unabated deforestation need simple with less labour involvement so that the limiting factors could be reduced for large scale replication, Since land under intense agriculture, grazing community land, denuded forests, mining and roads are badly afflicted with this devastation, we need immediate solutions that area how in cost with effective results. One such is botanical measure. Today’s degrading lands were in control of the green cover, the loss of the latter led to degradation.

LANDSLIDE AND BOTANY
Selection of a plant species for a given landslide is largely based on survey of the area, preferably only such species are used which bear ecological values for the region and are indigenous so that a vicious successional pattern of vegetation is restored.

The natural phenomenon of plant succession in a region has a strange – bearing with its ecological relationship. A particular vegetation type and its steps of changes, both progressive and retrogressive are strictly governed by the nature. Today’s climax stage, vegetation and have a certain balance uptake and release and are at equilibrium. It is noticeable that external factors operating in forest functioning obstruct this succession. Excessive interference like cutting and grazing, break new set of environment which is different from vegetational succession. Therefore in such cases, a new plant or vegetation appears is indigenous but less valuable from an ecological point-of- view. This new vegetation type is different in different places and largely depends upon the intensity of grazing taking place. Nevertheless, if these new communities are given protection for a considerable period, they lead to similar vegetational succession.

The above botanical knowledge has been the basic source of plant treatment for a particular landslide. Treatment of landslides with a certain group of species is nothing but acceleration of the already progressing natural process. The major source of plant selection for landslide treatment has been the vegetation of degraded areas. Different forces of degraded area develop specific plant species which bear intense potential of immediate colonization .Three categories of plants species are opted in the treatment viz. grasses, shrubs and trees. The specifications and details of these categories with reference to the present case study are given below:

TREES
In trees, there are a few species only which can be used in the treatment. The specific details of such species are presented in TABLE-1. The qualities of the trees species are their low soil moisture requirement and property of withstanding unfavorable conditions. They are light in biomass and coppice well.

Shrubs
Plantation of the shrubs in degraded areas is one of the major approach. Altered microclimate in landslide area affect soil moisture adversely and in such areas higher vegetational growth is not drought, high temperature and other adverse conditions.

Ecologically, shrubs have an upper hand on other plant species. They have tremendous resistance against unfovourable conditions. Therefore, shrubs are found in areas where soil is very poor. Besides, harvesting period of shrubs is very short and they coppice well. Most of the shrubs species may be grown by seeds as well by cutting. Following qualities encourage their introduction. These :

can be raised by vegetational propogation.
Can withstand unfavourable conditions,
Develop deep root system,
Coppice well, and
Can be easily grown in a wide range of soil.


GRASSES
A different type of vegetation tried for soil-stabilization, grasses have been found to be outdoing other because grasses

are amply available round the year.
can easily be grown in different climatic zones,
bear both deep and shallow root systems, which blinds more soil in comparison to other group of plants
can resist unfavourable conditions.
have very low moisture requirement for their survival,
coppice vigorously,
have high survival rate
can prevent grazing death as their perennial root system remains functional even when above ground biomass is browsed absolutely,
can be planted round the year by tussock except in their senescence stage.

Grasses have also got strong bearing with succession. A particular type of denotes stage of intensity of interference. Saccharum spontaneum colonizes bare land full of boulders. It is therefore after first treatment with Saccharum spontaneum, grasses like Pogonanthrum species, Neyrodia arundinacea should be tried. Besides, grasses like Cymbogogon fluroscence, Vetevaria zizanioides are also been plalnted. The details of different plant species have been given in Table 1

Background
Background A group of teachers with Botany background and students of HESCO in 1981 launched this measure to control unabled landslide zone between Kotdwara-Dugadda Road in district Pauri of U.P. hills. Constant threat of road block and loss of lives in monsoon had been a common feature here. To cope with, HESCO involved students in the uphill task. This group, well convinced with the vegetation role in land healing, launched treatment in 21 landslides. Out of this, 17 were well in control by 8 years. The rest, owing to deep slopes, needed mechanical measures which were then consequently over by the PWD. These areas today, are no more hazardous and present lush forest/green cover.

Geography of the area
The slides were located mainly in Shiwalik but few of them fall in the lesser Himalayan zone. The map denotes specific location of the sites treated. Geologically, the outer Himalaya comprise of soft territory, sedimentation sandstones, silt stones, slates clay and are readily subjected to mechanical disintegration. These ranges being in the front also face full force of the monsoon is very common in these areas.

METHODOLOGY
The first step for landslide treatment is to collect following information-

Area of the landslide
Nature of landslide
Type and amount of soil present
Topographical details- aspect,-slope,-indication etc.

All above information determine the type of species to be used. Temporary mechanical structures are also found very useful to support planted vegetation on collected soil.

Soil run-off study before and after treatment has been carried out. Treatment of landslide with different plant spp., through transplantation (i.e. grasses),cutting (i.e.shrubs) and seed broadcast,(i.e. woodlendia) have been taken up in the different landslides. Three different landslides which were total observed are detailed here.

In order to restore vegetation in the slides, the most common spp transplanted were-

A. TREE SPP.:

a) Wendlendia excelsa(Takuli)
b) Erythrina suberosa (Mandara)

B. SHRUBS:

a) Vitex negundo(Simali)
b) Agave cantula
c) Adhatoda vasica(Vasinga)

C. GRASS:

a) Vetevaria zizaniodes(Khas-Khas)
b) Saccharum spontaneum(Kans)
c) Cymbopogon flurosence(Saing-grass)
d) Eulaliopsis binata(Babad)
e) Pogonanthrum spp.(Khekla)
f) Eriophorum comosum(Murraya)

Preliminary treatment is given mainly through grasses. Tussock of indigenous grass was collected from land or by grass up in the nursery. The landslides are supported with semi-permanent mechanical structures(construction of check-dams). This is done in the cases where gradient is higher and deep gully formation is found. These structure support landslides for water diffusion and prevent excessive soil run-off.

Transplantation:
Since plantation in landslide area is difficult in the monsoon. It is therefore the treatment in the present study is given in the following manner.

Plantation	Duration
Plantation of grass other than -monsoon months(grasses)	I. Phase After Ist three months
Plantation of cutting of shrub/trees in winter seasons.	II. Phase 8-12 months
Plantation of shrubs/trees at the end of monsoon season(seed broadcasting and cutting plantation).	III. Phase 12-24 months

Slide I
The total area of the landslide was 2795 m and altitude was 442 m msl. The water holding capacity of the soil was 40.42%. The water holding capacity of the soil was 40.42%. The slide observed 12˚C-38˚ temperature. Average rain fall received was 300 mm. The soil loss ratewas 1.5 kg/minute.(Table 2,3). This landslide occurred in 1989 and developed deep scar bringing tones of soil, boulders and stone in 1991-92 in the following fashion.

Month:
Construction of check dams – May-June
Plantation of grasses/Agave – Nov-Dec
Seed broad cast – July/Aug
Cutting plantation – Nov-Feb

All the above treatments were repeated whenever any loss occurred in the vegetation due to heavy rain. It took three complete years for the control. The specific detail of vegetation applied is given in Table 4. In grasses, Saccharum spontaneum, Vetevaria zizanioides, Cymbogogan Eulaliopsis were applied. The highest survival was on Vetiveria and Cymbogogon. In shrubs, Vitex and Agave were applied showing good survival. Seed broad cast of Wendlendia excelsa were also made in July-August.

The total labour involved in this has been calculated on the basis of hrs.,mandays and cost involvement. It came to 350hrs, 43.7 days and Rs 1748. This shows fairly economical approach with permanent relief.(Table 7)

Landslide 2
This slide was located 8 Km. towards North-South of Kotdwara. This slide developed in 1987. The treatment in this slide started in 1989. The total cover area of the slide was 4220 m² located at 590 m msl. The water holding capacity was 30-32%. The other details of the slide are given in Table 2.3. The soil run off rate in this slide was 2.5 Kg./m. This treatment in this slide was as follows:

- Construction of small check dams
- Plantation of grasses
- Seed broadcast
- Cutting plantation

A total of 5 type of grasses were planted here. Besides above, Pogontherum spp.was also tried. All the species behaved fairly good in this slide. The survival % ranged from 40 to 90%. Similarly among the shrubs Vitex and Ipomea showed good result. Wendlendia excelsa sown by seeds showed 70% survival. After 2 years of regular treatment, the soil run off rate dropped to 0.75 gm/min.(Table 5)

The analysis of hrs/mandays/cost involved in the slide show encouraging results. This involved 184hrs. 23 mandays and Rs.805 in a period of one year for complete relief. Details of this is given in Table 7.

OTHER GROUPS ASSOCIATES
Treatments of landslides with botanical cum mechanical structures is the only potential solution. Mechanical structures provide immediate relief while botanical a permanent solution.

This theme of the organization was scheduled by various other organizations particularly NGOs and forest departments and Directorate General of Border Road. These organization also have followed the similar technique in their problem area in consultation with HESCO. A preliminary information on the involvement of other agencies with HESCO is also given in Table-9.