FOREWORD

The FAO Watershed Management Field Manual is published within the FAO Conservation Guide Series as Conservation Guide No. 13 and will consist of seven separate volumes:

Watershed Survey and Planning

Slope Treatment Measures and Practices

Vegetative and Soil Treatment Practices

Road Design and Construction in Sensitive Watersheds (this volume)

Landslide Prevention Measures

Gully Control

Water Harvesting

The objective of this Manual is to assist professionals concerned with the planning and implementation of watershed management activities by providing practical information supported by examples from a wide variety of situations. However, the watershed situation in each country is unique and it is impossible to provide step by step solutions which will apply in any specific area. The user of the Manual is, therefore, invited to add the local experience and information deemed necessary.

We wish to acknowledge the valuable work of Mr. Peter Schiess, Associate Professor of Logging Engineering, University of Washington, and Ms Carol A. Whitaker, Hydrologist, on which this volume was based; it has been prepared for publication by Mr. T. Michaelsen of the Forest and Wildlands Conservation Branch, with the collaboration of Mr. R. Heinrich and Mr. T.A. Frisk-Smith in the Forest Logging and Transport Branch of the Forest Industries Division. It is hoped that the publication will be useful to all professionals involved in watershed management activities.

J.P. Lanly
Director
Forest Resourses Division
Foresty Department

ABSTRACT

The document provides detailed specifications for road design and construction in mountain areas in sensitive watersheds where on-site protection of the road itself as well as the downstream effects of soil disturbance and changes in drainage patterns are important considerations. Protection includes provision for adequate drainage as well as surface and slope protection measures. Road construction and maintenance techniques- are adapted to conditions of low traffic volumes in steep terrain.

Conversion Table: English - Metric Units

1. Length

From

To

cm

m

km

Multiply by

inch

2.54

2.54 * 10-2

2.54 * 10

feet

3.05 * 10

3.05 * 10-1

3.05 * 10-4

yards

9.14 * 10

9.14 * 10-1

9.14 * 10-4

miles

1.61 * 105

1.61 * 103

1.61

2. Area

From

To

cm²

m²

km²

Multiply by

square inch

6.45

6.45 * 10-4

6.45 * 10-10

square feet

9.29 * 102

9.29 * 10-2

9.29 * 10-8

square yard

8.36 * 103

8.36 * 10-1

8.36 * 10-7

square mile

2.59 * 1010

2.59 * 106

2.59

3. Volume

From

To

cm³

litre

m³

Multiply by

cubic inch

1.64 * 101

1.64 * 10-2

1.64 * 10-5

cubic feet

2.83 * 104

2.83 * 101

2.83 * 10-2

cubic yards

7.65 * 105

7.65 * 102

7.65 * 10-1

gallons

3.78 * 103

3.78

3.78 * 10-3

4. Pressure

From

To

gr/cm²

kg/cm²

kg/m²

Multiply by

lb / inch2

7.031 * 101

7.031 * 10-2

6.896

lb / feet2

4.882 * 10-1

4.882 * 10-4

4.788 * 10-2

tons (short) / feet2

9.766 * 102

9.766 * 10-1

9.578 * 10