8.1 Reconnaissance level studies
8.2 Pre-feasibility and feasibility studies
The main purpose of land evaluation is to provide information on which to base planning and investment decisions. Decisions are made at various stages of development from reconnaissance through to detailed project planning and implementation. At each stage, the products of the land evaluation include reports and maps at intensities and scales outlined in Table 3 (Chapter 1). In the case of project development reports, it is usual to produce a detailed technical Main Report with supporting Annexes and an Executive Summary. Apart from the final reports, it may also be necessary to produce regular progress reports and interim reports. These are the basis for discussions between the investor, client and consultant which lead to the major policy decisions.
Some illustrations of the types of presentation which are relevant at various stages of the investigations from reconnaissance through to project planning are given in the following paragraphs.
The results of reconnaissance surveys are usually presented on maps at scales of 1:100 000 to 1:250 000. They may be concerned with the preparation of a Master Plan for land and water resources development including the selection of priorities. At the level of individual river basins, maps should define areas for catchment protection, flood zoning, reclamation, swamp and tidal areas, and areas with potential for irrigation development. The report should list the possible development options and their respective merits and give recommendations and terms of reference for further, pre-feasibility or feasibility studies of each of the priority projects identified.
Land suitability categories at reconnaissance level will often include fewer classes than for more intensive studies (e.g. S1, S2 and N). LUTs will generally be broadly defined and the economic evaluation will indicate production and income potential at a macro level. Land systems will be delineated to distinguish broadly land which is promising for specific kinds of irrigation and rainfed agriculture, from land which is not. The requirements and limitations of the LUTs are less precise than is needed in planning a particular project. For example, Table 29 indicates the major climatic and soil characteristics required for lowland rice in Indonesia (Bunting 1981) and is an illustration of the type of information needed for Format 1 at a reconnaissance survey level.
To illustrate the type of map that might be presented as a result of a reconnaissance study, Figure 3 shows the result of a large river basin planning study in Sri Lanka. The original FAO (1968b) study envisaged a development programme of 30 years to develop the land and water resources of the Mahaweli river. The results of the study indicated the possibility of irrigating 237 000 ha of new rice land and the provision of additional water seasonally to 104 000 ha of existing single crop rice land. The proposals were for a phased programme to develop a series of irrigation schemes, some in the river basin of the Mahaweli itself, and others in adjacent river basins with supplemental water from the Mahaweli river via tunnels, transbasin canals or diversion structures. The development programme included power generating headworks, together with storage dams and reservoirs to provide water in the dry season. Figure 3 shows the areas that were designated for phased development as a result of this evaluation. Feasibility studies of several of these individual areas were later commissioned leading to project implementation.
Table 29 FACTORS THAT MAY DETERMINE LAND SUITABILITY CLASS FOR LOWLAND RICE IN INDONESIA 1/
|
DESCRIPTION OF THE LAND USE TYPE: |
||||||
|
Land Characteristic or Land Quality |
Units |
CRITICAL LIMITS |
||||
|
s1 |
s2 |
s3 |
n |
|||
|
Length of growing period |
days |
120 |
105-120 |
95-105 |
95 |
|
|
Average temperature over the growing period |
°C |
24-26 |
26-28 22-24 |
28-30 20-22 |
30 20 |
|
|
Water requirements (rainfall and irrigation) |
mm/yr |
>1 600 |
1 300-1 600 |
1 000-1 300 |
<1 000 |
|
|
Soil drainage class 2/ |
|
1, 2 |
3, 4 |
5 |
|
|
|
Soil texture 3/ |
|
8, 9 |
6, 7 |
5 |
1,2,3,4 |
|
|
Rooting depth |
cm |
25 |
25 |
25 |
25 |
|
|
Soil pH |
|
5.5-6.5 |
6.5-7.5 5.0-5.4 |
7.6-8.2 4.5-4.9 |
8.24.5 |
|
|
Soil salinity |
dS/m |
3 |
3-5 |
5.1-6.5 |
6.6-8 |
|
|
Nutrient uptake/(nutrient removal in brackets) |
N |
kg/ha |
160 |
110 |
75 |
48 (30) |
|
|
P |
|
32 |
24 |
18 |
14 (9) |
|
|
K |
|
250 |
170 |
110 |
60 (10) |
Adapted from Bunting 1981.1/ Note that not all the above land characteristics would be class-deter-mining. Land suitability class is based on those that are, taking into account their 'Interactions' (Section 6.2) and 'Significance' (see Section 6.3).
2/ Key to drainage classes: 1 = very poorly drained, 2 = poorly drained, 3 = imperfectly drained, 4 = moderately well drained, 5 = well drained, 6 = somewhat excessively drained, 7 = excessively drained.
3/ Key to texture classes: 1 = gravel, 2 = coarse sand, 3 = medium sand, 4 = fine sand, 5 = loamy sand, 6 = sandy clay loam, 7 = loam, 8 = sandy clay loam, 9 = silt loam, 10 = silt, 11 = clay loam, 12 = silty clay loam, 13 = sandy clay, 14 = kaolinitic clay, 15 = silty clay, 16 = mixed clays, 17 = structured montmorillonitic clay, 18 = massive montmorillonitic clay.
The maps presented in pre-feasibility and feasibility studies are typically at scales from 1:25 000 to 1:50 000 with smaller scale supporting maps as appropriate for the executive summary. In the absence of full knowledge of the water supply and the development costs, land suitability may be classified on the basis of net farm income. An 'irrigable' area can later be delineated from within the 'provisionally-irrigable' area using NIIB as an economic measure of suitability. Figures 4a and 4b are small-scale maps depicting 'provisionally-irrigable' and 'irrigable' land at successive stages for the Southern Conveyor Project in Cyprus (Water Development Department, Cyprus and LRDC, 1982).
At the 'provisionally-irrigable' level, several: land- use alternatives will usually be presented with a classification of their respective suitabilities on different areas of land, and with subclasses indicating some of the land development requirements (e.g. drainage) for contiguous areas amalgamating the individual mapped land units. Land suitability maps may be presented for each LUT, or a single map with a tabular legend indicating the alternative LUTs and their suitability classes and subclasses can be presented, using appropriate adaptations of Format 5 (Table 9,.Chapter 2). The maps may be used independently of the report and should therefore be self-explanatory. Ah example of a legend that illustrates the classification of the land units for some of the LUTs outlined in Table 11 (for Bali, Indonesia, see Section 4.1.2) is given in Table 30.
Table 30 LAND SUITABILITY CLASSES AND SUBCLASSES FOR LAND UNITS AND LUT COMBINATIONS IN AN IRRIGABLE CLASSIFICATION ILLUSTRATING A MAP LEGEND
|
Land Utilization Types
|
IRRIGATED RICE LAND |
Irrigated citrus |
Coconuts (rainfed) |
Rainfed food crops |
||||
|
Two rice crops/year |
Rice and two palawija crops/year |
Rice and soybean/year |
One rice/fallow |
|||||
|
Land units on map and area |
LUT 1.1.1 |
LUT 1.2.2 |
LUT 1.2.3 |
LUT 1.1.4 |
LUT 1.5 |
LUT 2.1 |
LUT 2.2 |
|
|
|
ha |
|
|
|
|
|
|
|
|
1 |
10 |
N1m |
S3m |
S2m |
S1 |
S3rm |
S1 |
S1 |
|
2 |
15 |
N1m |
S3m |
S2m |
S1 |
S3rm |
S1 |
S1 |
|
3 |
6 |
N1m |
N1m |
S2t |
S2t |
S3rm |
S1 |
S2p |
|
4 |
34 |
N1m |
N1m |
N1m |
N1m |
S2d |
S1 |
S1 |
|
5 |
25 |
S1 |
S1 |
S1 |
S1 |
S2r |
S1 |
S1 |
|
6 |
18 |
S2m |
S2m |
S1 |
S1 |
N1d |
S1 |
S1 |
|
7 |
20 |
N2 |
N2 |
N2 |
N2 |
N2 |
N2 |
N2 |
|
etc. |
|
|
|
|
|
|
|
|
1/ LUT numbers refer to Table 11.
Land evaluation will be only one of the aspects covered in a pre-feasibility or feasibility report. The form of the report required has been outlined in Guidelines for the Preparation of Irrigation and Drainage Projects, (FAO 1983).
It is necessary to bear in mind the different categories of readers who will use the report, ranging from the general reader who wants the whole picture in a few pages, to the specialist who will scrutinize the detailed aspects of his speciality. There are no hard and fast rules as to the form that a project preparation report must take, but most major external financing agencies prefer to receive a relatively short Main Report of about 40 pages on a project, which is supported liberally by annexes containing relevant data, detailed descriptive material, land evaluation reports and maps, preliminary designs, specifications and cost estimates, and other background material.
The Main Report should begin with a short executive summary of the project's salient features for administrators and politicians without the inclination or time to read the following chapters. Alternatively, an Executive Summary can be presented as a separate document including summary maps showing the 'provisionally-irrigable' or 'irrigable' areas and the irrigation and drainage layout.
A suggested sequence of chapters in a Main Report is as follows. The chapter contents are indicated in Table 31.
Summary and Conclusions
I. Introduction
II. Background
III. Project Rationale
IV. The Project Area
V. Project Design Considerations
VI. The Project
VII. Organization and Management
VIII. Agricultural Development and Production
IX. Markets, Prices and Financial Results
X. Benefits and Environmental Impact
XI. Outstanding. Issues and Follow-up
A typical set of Annexes to accompany a Main Report is presented below although the number of volumes and their titles will vary from project to project.
1. Surface Water Resources
2. Groundwater Resources
3. Land Evaluation Report and Maps
4. Irrigated Agricultural Development
5. Engineering (Dam and Diversions)
6. Engineering (Conveyance System)
7. Capital and Recurrent Costs
8. Project Institutions
9. Marketing and Prices
10. Financial Results
11. Economic Analysis
The nature and extent of annexes should be such that they anticipate and answer questions likely to be asked by both the appraisal team and the implementing agency. These aspects are further discussed in Chapter 9.
Table 31 TYPICAL CHAPTERS AND CONTENTS LIST FOR A MAIN IRRIGATION PROJECT REPORT
|
|
Summary and Conclusions |
|
I. |
INTRODUCTION |
|
II. |
BACKGROUND |
|
III. |
PROJECT RATIONALE |
|
IV. |
THE PROJECT AREA |
|
V. |
PROJECT DESIGN CONSIDERATIONS |
|
VI. |
THE PROJECT |
|
VII. |
ORGANIZATION AND MANAGEMENT |
|
VIII. |
AGRICULTURAL DEVELOPMENT AND PRODUCTION |
|
IX. |
MARKETS, PRICES AND FINANCIAL RESULTS |
|
X. |
BENEFITS AND ENVIRONMENTAL IMPACT |
|
XI. |
ISSUES AND FOLLOW-UP |
