A grassed waterway is associated with channel terraces for the safe disposal of concentrated run-off, thereby protecting the land against rills and gullies. A waterway is constructed according to a proper design and a vegetative cover is established to protect the channel section against erosion because of the concentrated flow. In the alluvial soils of the Doon Valley under the humid subtropical climate, Panicum repens was the best-suited grass, followed by Brachiara mutica, Cynodon plectostachyus, Cynodon dactylon and Paspalum notatum. The suitability of a grass was based on the cover it gave, the ease with which it was established and the forgae yield obtained from it.

EVALUATION OF EFFECTS OF SOIL AND WATER CONSERVATION ON AGRICULTURAL LAND.   The beneficial effects of conserving soils moisture by constructing bunds and levelling the land have been extensively demonstrated in the semi-arid alluvial plains of Uttar Pradesh where 35 per cent, 63 per cent and 98 per cent increase in the yields of kharif and rabi crops has been obtained by bunding alone, levelling alone and bunding-cum-lenelling respectively. Bunding has increased the yields of Setaria, cotton and johar by 18 per cent, 11 per cent and 17 per cent in large-scale field trials in Tamil Nadu.

Contour-bunding has not only increased the yield of crops in the dry farming areas in Maharashtra, but has also increased the water level in the wells and the employment oppurtunities as the age of bunding increased.

ESTIMATION OF PEAK RATE OF RUN-OFF. $nbsp For designing various structures and carrying out mechanical measures to control erosion for the safe disposal of run-off, such as grassed waterways and check dams, the estimation of peak rate of run-off is an important design criterion. Three monographs have been developed to estimate the peak rate of run-off by using three different method\s, viz. The Rational Method, the Cooks Method and the Hydrologic Soils-Cover Complex Method.

GULLY-EROSION CONTROL AND RECLAMATION. $nbsp It is estimated that about 2.3 m ha (5.75 m acres) of land in India is affected by severe gully erosion. These gullies are an indication of very bad management of the land resources. Apart from the fact that the gullied land has been completely destroyed, the gullies are a menace to the adjoining tablelands.

Whereas, as a result of gully erosion, the land resource, one of the most important natural resources we have, is completely lost, the people along the river banks suffer from innumerable hardships. The ravine lands pose a socio-economic problem as they harbour dacoits and undesirable social elements. Also, the ravine lands are one of the chief sources of sediment which chokes the reservoirs in the country.

The gently sloping nature of the land, the loamy-sand, the sandy-loam and the silty-loam texture of the soil, intense rains in the monsoon, the improper land use by resorting to overgrazing, the biotic interference with the natural vegetative cover and the faulty agricultural practices are the chief causes of gully erosion all over India.

Classification of gullies.   Any system of gullies has an independent catchment, with a regular stream which has been termed the "drainage system". In each drainage system, it has been observed that gullies with defined side slopes, bed width and depths occur in a regular order. In the upper reaches of the drainage system, the gullies are wide and shallow, with varying side slopes. The middle part of the drainage system is usually deeper, wider and has uniform side slopes normally up to about 15 per cent. The lower portion of the drainage system which is nearer to the main river is usually very deep, has steep side slopes and is associated with intricate branch gullies. The gullies have been classified as follows :

While the general pattern of land-capability classification is based on the recommendations of the Soils-Survey Manual, the interpretation in relation to slope classes and the susceptibility to erosion hazard by active gullies has been modified to suit the conditions in ravine lands. In ravine lands, the slope of the land and the nearness of gullies are the most important and dominant factors which vary widely and influence land capability. The land-capability classification specifications for the ravine lands, as influenced by the slope of the land and the gully erosion hazard, are given below :

Land-capability classes II, III, IV, VI and VII are to be annexed by symbol "e", indicating damage by the past erosion, the present hazard and the future susceptibility to gully erosion.

Control of gullies and their reclamation for various land uses.   The practices described below are arranged in the order in which they should be adopted; the cost of their execution increases progressively.

Closure to grazing and other biotic interference.   A study of the natural flora of the eroded areas has shown that only poor types of annual and unpalatable grasses are growing in place of the desirable climax associations which should normally exist in the prevailing soil-climatic environment.

It is reported that at Vasad in Gujarat, as result of closure to grazing and other biotic interference, (a) Aristida funiculata and Themada triandra were first replaced by Apluda mutica (a tall annual grass) and then by the perennials, such as Eremopogon foveolatus, Heteropogon contortus, Dicanthium annulatum and Cenchrus sp., (b) the loss of soil and water progressively decreased from the area as the natural vegetation improved , and (c) there was not only qualitative but quantitative increase in the yield of grasses. Similar results have been reported on the clay loam and clay soils of the Chambal ravines where closure to grazing and biotic interference resulted in the qualitative and quantitative increase of useful species, such as Dicanthium annulatum, Cenchrus ciliaris and Apluda mutica. Under the upper Damodar catchment conditions, it has been observed that closure to grazing reduced the soil loss from 3.3 tonnes/ha (under overgrazing condition) to only 0.6 tonnes/ha.