WATERSHED MANAGEMENT. Guidelines for Indian Conditions E.M. TIDEMAN OMEGA SCIENTIFIC PUBLISHERS. New Delhi PREFACE

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1 Page 1 of 13 WATERSHED MANAGEMENT Guidelines for Indian Conditions E.M. TIDEMAN OMEGA SCIENTIFIC PUBLISHERS New Delhi PREFACE Soil and water are of crucial importance for mankind. The continuing and ever accelerating depletion of the available soil and water resources in India and elsewhere in the world is a matter of grave concern. The technical knowledge as to how to arrest this degradation and how to conserve soil and water exists, but this knowledge has been applied only on a limited scale. One of the reasons is that the existing knowledge is not easily available to those who should apply it. This book brings together the technical and some of the socioeconomic knowledge available for successfully implementing watershed management. The multidisciplinary approach involving all factors influencing the well-being of the people of the watershed is called watershed management. Soil and water conservation is a very important aspect of watershed management but in order to realize the highest benefits for the people other aspects like the socioeconomic situation should not be neglected. Besides the purely technical aspects of soil and water conservation, the importance of people's participation cannot be sufficiently stressed. Only if the people who live in the area concerned request, agree to, and understand the work to be carried out, will they actively participate in its implementation, cooperate in its maintenance, fully utilize the opportunities offered, and make them sustainable in general. After all, the people of the watershed themselves are the most important factor of influence in the degree of degradation or conservation; not.only by being responsible for the works implemented by the government but particularly by their agricultural operations and other activities. One can invent the wheel only once. For this reason major parts of the contents of this book have been taken and edited from existing publications. Especially valuable resources have been the various publications of the Central Soil and Water Conservation Research and Training Institute in Dehradun. Within the framework of various Indian schemes for soil and water conservation, the Indo-German Bilateral Project 'Watershed Management' was established in the Ministry of Agriculture, New Delhi, in The

2 Page 2 of 13 project is financed by the Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung (BMZ- German Ministry of Economic Cooperation and Development), implemented by the Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH (German Agency for Technical Cooperation) and executed by RODECO Consulting GmbH. This book is one of the results of the Indo-German Bilateral Project Watershed Management' By bringing together in one book the most important aspects of the existing knowledge in watershed management, it is hoped that this book will contribute in facilitating the access to and the implementation of this knowledge. These guidelines are intended as a reference for professionals working in the field of watershed management from either governmental or non-governmental organizations. The book could also be used by students in agricultural colleges and institutions. E.M. TIDEMAN CONTENTS 1 INTRODUCTION Soil Erosion Erosion Problems Why Soil Conservation is Needed Available Conservation Technology Agricultural Lands Contour Farming Mechanical Measures Runoff Harvesting, Storage and Recycling Non-agricultural Lands Fuel-Fodder Plantation Ravines Types of Erosion Involvement of People Watershed Approach Watershed Management The Concept of Priority Watersheds Principal Factors Influencing Watershed Operations Physiography Size Shape Land Slope Drainage Density and Pattern Soils and Geology Land Use Vegetative Cover Design Peak Runoff Rate 13

3 Page 3 of Precipitation Socio-economic Factors Organization Analysis after Treatment of Land with Soil Conservation Measures The Hydrologic Cycle 15 2 SOILS Soil and Water The Soil Soil Composition Soil Profile Soil Texture Soil Structure Entry of Water into the Soil The Infiltration Process Infiltration Rate Factors Influencing the Infiltration Rate Soil Moisture Conditions Soil Moisture Content Saturation Field Capacity Permanent Wilting Point Available Water Content Groundwater Table Depth of the Groundwater Table Perched Groundwater Table Capillary Rise Soil Conditions for Plant Growth How Plants Grow in the Soil Essential Food Elements Required for Plant Growth How Soils Feed the Plant What Are the Toxins Present in the Soils? Miniature Living World in the Soil How To Supply Plant-food in Deficient Soils Determination of Nutrient Deficiencies 36 3 LAND CAPABILITY CLASSIFICATION FOR WATERSHED MANAGEMENT Introduction Purpose of Land Capability Classification Soil Profile Characteristics External Features of Land Climatic Factors Classification Land Capability Group 39

4 Page 4 of Land Capability Classes Land Capability Subclasses Land Capability Units Mapping Units Colour Notation Characteristics of Various Land Capability Classes The Main Classification in Eight Classes Other Classifications Classification for Himalayan Region Gully Classification Land Capability Classification for Ravine Lands Land Capability Rating Table Determination of the Land Capability Class Recommended Land Use and Soil Conservation Practices for the Eight Capability Classes 3.5 Limitations and Improvement Soil and Land Capability Suitability Surveys Soil Survey New Survey Supplemental Survey Soil Survey by Traverse Method Soil Survey by Aerial Photo-interpretation Slope Analysis Land Capability and Suitability Classification A 'Treatment-oriented' Capability Classification Procedures for Producing a Land Capability Map New Scheme of Land Capability Classification Diagram of Mapping Procedures for Land Capability an Land Use Maps 4 RAINFALL AND METHODS OF MEASUREMENT Introduction Forms of Precipitation Formation of Rainfall Moisture in Atmosphere Mechanism of Cooling of Air Condensation Mechanism Mechanism of Growth of Droplets Accretion Process Rainfall Pattern in India Annual Rainfall Rainfall Parameters Amount of Rainfall Duration

5 Page 5 of Intensity Rainfall Frequency Rainfall Measurement Raingauge Types Non-recording or Standard Raingauges Recording Raingauges Siphon Type Tipping Bucket Type Weighing Bucket Type Selection of Raingauge Sites Installation, Operation and Maintenance Standard Raingauge Recording Raingauge Analysis of Rainfall Chart Analysis of Rainfall Chart for Intensity Graphical Representation Of Rainfall Intensity Calculation Of Intensities for Different Durations Intensity-Duration Relationship Rainfall Intensity-Duration-Frequency Relationship Average Depth of Rainfall over an Area Arithmetic Mean Thiessen Method Isohyetal Method 75 5 ESTIMATING RUNOFF Introduction Runoff Processes Factors Affecting Runoff Quantities and Rates of Runoff Time of Concentration Intensity and Duration of Rainfall Hydrologic Conditions Vegetative Cover Conservation Practices Topography Prediction of Design Peak Runoff Rational Method Cook's Method Hydrologic Soil Cover Complex Number Method The Table Method Estimation of Direct Runoff from Rainfall TOPOGRAPHIC SURVEYING Elementary Surveying Equipment 103

6 Page 6 of Chain and Tape Measuring Rod Plumb Bob Carpenter Level Ranging Poles Pegs Setting Out Straight Lines Placing of Ranging Poles Setting Out Straight Lines Setting Out Straight Lines over a Short Distance Setting Out Straight Lines over a Long Distance Setting Out Straight Lines over a Ridge or a Hill Setting Out Contour and Graded Contour Lines and Slopes Boning Rods Description Use of Boning Rods Setting Out Horizontal Lines Setting Out Slopes The N-Frarne Level Description Testing the N-Frame Level Setting Out Contour Lines Setting Out Slopes The Flexible Tube Water Level Description Use of the Flexible Tube Water Level Setting Out Contour Lines Measuring Differences in Elevation The Hand Level Description Setting Out Contour Lines Measuring Differences in Elevation Engineering Surveying Introduction Fundamentals of Surveying Measurement of Dimensions Determining Horizontal Position Determining Vertical Position Surveying Equipment Checking Instruments for Adjustment Hand Signals Survey Notes and Symbols 134

7 Page 7 of Measurement of Horizontal Distances Pacing Chaining Stadia Aerial Photographs Differential Levelling General Common Terms Used in Levelling Setting up the Level Bench-level Circuit Grid Surveys ENGINEERING MEASURES FOR EROSION CONTROL IN AGRICULTURAL LAND 7.1 Contour Cultivation Contour Bunding Introduction Planning of Contour Bunds Cross-section of the Contour Bunds Bund Height Height of Bund with 30 cm of Impounding Contour Bund to Store Runoff from 24 Hour Rain Storm of a Given Frequency Staking the Bund Alignment Permissible Deviations on Alignment Construction of Contour Bunds Area Lost Due To Contour Bunding Computation of Earthwork for Bunding Maintenance of Bunds and Outlets Planting of Grasses and Trees Drainage of Excessive Water (Surplusing Structures) Purpose and Types of Structures Design of Surplusing Structures Graded Bunding Introduction Outlets Design of Graded Bunding Spacing Grade Cross-section of Channel Number of Outlets Planning Graded Bunding Construction of Graded Bunding Maintenance of Graded Bunding during First Year Advantages and Limitations of Graded Bunding

8 Page 8 of Advantages Limitations Bench Terracing Objectives and Types of Bench Terraces Design of Bench Terraces Terrace Spacing Terrace Gradient Terrace Cross-section Alignment of Terraces Terrace Execution Computation of Width of Terrace and Earthwork for Bench Terracing Cost of Bench Terracing Bench Terraces with Stone Walls General Determining the Interval between Bench Terraces of Level Crosssection Determining the Interval according to the Presumed Stable Slope The Retaining Wall Drainage of Gravitational Water Disposal of Runoff Water Cost of Construction Land Levelling and Grading Factors Governing Land Levelling Land Levelling Design The Plane Method Calculation of Centroid The Elevation of the Plane at the Centroid Earthwork Volumes Construction Procedures Setting Grade Stakes Job Planning Construction Grassed Waterways General Planning Construction, Establishment and Maintenance Diversion Drains Design of a Diversion Channel WATER CONSERVATION AND HARVESTING Introduction Water Conservation Methods for Crop Land Broad Bed and Furrow System (BBF) Ridging and Tied Ridging

9 Page 9 of Contour Furrow Inundation Methods Treatment of Catchments Natural Catchments and Minor Changes Shaping Catchments Small Storage Structures Introduction Objectives and Data Required Types of Storage Structures Design Data Required Small Earth Dams Planning Earth Dams Spillways The Embankment or Darn Wall Construction Sequence Computation of Storage Capacity Common Terminologies Design Examples Small Weirs Sand Dams Drought Farm Pond Selection of Site Construction Estimation of Volume of a Pond Nala Bunding Off-stream Storage General Rectangular Tanks Ring Tanks Turkey's Nest Tank Losses of Stored Water Seepage Losses Evaporation Losses Developing Groundwater Groundwater Recharge Groundwater Extraction Water Harvesting for Trees and Shrubs General Methods and Techniques AGRONOMIC MEASURES IN SOIL AND WATER CONSERVATION Land Use and Conservation Agronomy Introduction 233

10 Page 10 of Choice of Crop Use of Cover Crops Planting Time Root Factors Land Preparation Contour Farming Crop Geometry Mulching Strip, Mixed and Intercropping Weather Aberrations and Cropping Adoption of Organic Manures, Green Manure and Fertilizers Residue Management Crop Rotations Grasses Vegetative Hedges and Buffers Grassland Management Introduction Principles of Grassland Management Balancing Numbers of Animals with Grazing Capacity Grass Covers of India Soil and Moisture Conservation Techniques in Grasslands Controlled Grazing Fencing Area Closure Cut and Carry Land Preparation Grassland Improvement Weed Control Eradication of Noxious Plants Watering Points Use of Fertilizers Grazing Management Introduction Methods of Grazing Agroforestry Introduction Objectives of Agroforestry Agroforestry Systems Shifting Cultivation Taungya Cultivation Silvi-pastoral Systems Pastoral silvicultural system 260

11 Page 11 of Silvi-agriculture System on Arable Land (Agri-silvi System-Class I to IV) Agricultural Crops with Commercial Trees Intercropping with Horticultural Trees Farmers' Preferences for Agro-forestry Species Forest Regeneration Natural Regeneration Regeneration by Seeds Regeneration by Coppice Artificial Regeneration Sowing Seed Treatment Seedling Establishment Sowing Methods Soil Working Techniques Managed Plantations and Selection of Species Nursery Methods and Practices Introduction Nursery Preparation Seedling Growing Planting Maintenance and After-care Watershed Protection Horticulture General Introduction Soil Moisture Conservation and Water Harvesting People's Involvement Agri-horti System Homestead Gardens Social Forestry Orchards Demonstration Schemes Scope of Fruit Cultivation in India Groups of Fruits How to Cultivate What to Grow When and How to Plant Watering Pruning Fruit Ripening Classification of Fruit Crops Fruit Crops in Wastelands Cashew (Anacardium occidentale L.) 293

12 Page 12 of Zizyphus (Ber) Guava (Psidium guava L.) Indian Gooseberry (Aonla) Citrus Fruits EROSION CONTROL MEASURES FOR NON-AGRICULTURAL LANDS General Introduction Soil Conservation on Wastelands General Eroded Wastelands Swamps Contour and Staggered Trenching Contour Trenching Trench Types Design and Construction Gully Control Structures Temporary Control Structures Cheekdams Brushwood Checkdams Semi-permanent Control Structures Loose Rock Dams Log Dams Gabion Checkdams Permanent Control Structures General Structure Selection Drop Spillway Design of Drop Spillway Chute Spillway Drop Inlet Spillway Sediment Retention Structures Introduction Sediment Basin Design Calculation of Required Surface Area and Storage Volume Retaining Walls Structures Subjected to Water Pressure General Condition of Stability Structures Subjected to Earth Pressure General Checking for Stability Gully and Ravine Reclamation 340

13 Page 13 of General Control of Gullies and Their Reclamation for Various Land Uses Control of Gullies Reclamation of Gullies for Cultivation Design of Composite Checkdam WATERSHED MANAGEMENT Introduction Definition of Watershed Size of the Watershed How Does a Watershed Affect the People Watershed Characteristics Causes and Consequences of Watershed Deterioration Definition of Watershed Management Objectives of Watershed Management Watershed Approach in Government Programmes People's Participation Definition of 'People's Participation' To Pay Incentives or Not? Mobilization of Participation People's Organization Conservation Farming General Programming Conservation Farming Watershed Management Plan General Identification of Watershed Problems, Objectives and Priorities Collecting Existing Data Quick identification of Watershed Problems Determining Main Objectives and Priorities Socio-economic Survey General Collection of Data Analysis of Problems Watershed Map Format for Watershed Management Plan 361 SELECT BIBLIOGRAPHY 371