Introduction to Integrated Coastal Area Management

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Introduction to Integrated Coastal Area Management

7. Methodologies, analytical tools and technologies used in ICAM

There are a number of methodologies, analytical tools and technologies available to ensure that decisions made during the implementation phase of any integrated coastal area management (ICAM) program is sound and well-informed. These include (i) coastal resource inventories and environment profiles, (ii) mapping and geographical information systems (GIS), (iii) remote sensing, (iv) rapid appraisal techniques, (v) environmental impact assessment, (vi) benefit-cost studies, and (vii) risk assessment.

7.1. Inventory of coastal resources

7.1.1. Land Resources Inventory and Land Evaluation

This section deals with the land resources inventory and its evaluation. There are two major methods are available to us. They are FAO method that is generally called land suitability analysis and the other is USDA method and called land capability analysis generally. Capability analysis is for general land use analysis. Suitability analysis is for particular purpose. For example land capable for agriculture purposes is a capability method on the other hand, land suitable for wheat is a suitability method. Both methods share common terms, definitions and procedure to some extent. Before we go in detail let us see what are all the terms and definitions are related these methods.

A long but informative definition for ‘land’ is defined as ‘an area of the earth’s surface which embrace all reasonably stable, or predictably cyclic, attributes of the biosphere vertically above and below this area including those of the atmosphere, the soil and underlying geology, the hydrology, the plant and animal populations, and the results of past and present human activity, to the extent that these attributes exert a significant influence on present and future uses of the land by humans’(Food and Agriculture Organization of the United Nations, 1985). Note that in this definition, ‘land’ is much more than ‘soil’, ‘topography’, ‘climate’, ‘political division’, etc. and in fact is an integrated geographic concept (both physical and human). It includes human occupation to the extent that this influences land use.

7.1.1.1. Land units / Resources mapping units

Land units are nothing but the homogenous piece of land in which all-physical characteristics like soil; geology, rainfall, slope etc. are same. When the evaluation starts with data from a natural resources data base (e.g., a soil survey or climate map), the map unit as shown on any resource map as a single legend class, or as derived from an intersection of several maps (e.g., soil type overlaid with climate type), is considered sufficiently homogeneous with respect to the land characteristics implied by the legend, and forms the unit of analysis. The map unit of the natural resource inventory is also called a legend class or category. This has been the usual approach for physical land evaluations based on soil survey interpretations or agro-ecological zones.

7.1.1.2. Management units

A management unit, sometimes termed a decision area, is an area of land that the manager (farmer or planner) will treat or allocate differently. These may be quite large, e.g., in large-scale mechanized monocultures, or very small, e.g., in subsistence agriculture. If the objective of the evaluation is to determine the land use options for existing management units, it makes sense to use these directly as the evaluation units. Each management unit is uniquely located, so geographic considerations can be included in the analysis.

7.1.1.3. Economic units

An economic unit is the collection of management units controlled by one land manager. Although decisions will be made separately for each management unit, the land manager (or zoning agency) may well require a mix of activities spread out over the entire economic unit or planning area, because the overall benefit of the economic unit is what is important to the manager, not the benefit from each management unit.

7.1.1.4. Planning areas

A planning area is the collection of management units influenced by a planning agency. Although decisions will be made separately for each management unit, the zoning agency usually has a mix of objectives that must be satisfied by the planning area, as well as geographic constraints on simultaneous land allocation. Therefore, the entire planning area must be considered as a unit, in order to arrive at correct land allocation decisions.

7.1.1.5. Major Kind of Land Use

“A major subdivision of rural land use, such as rainfed agriculture, irrigated agriculture, grassland, forestry, recreation” (Food and Agriculture Organization of the United Nations, 1976).

7.1.1.6. Land Utilization Type (LUT)

“A kind of land use described or defined in a degree of detail greater than that of a major kind of land use (q.v.)” (Food and Agriculture Organization of the United Nations, 1976).

“In the context of irrigated agriculture, a land utilization type refers to a crop, crop combination or cropping system with specified irrigation and management methods in a defined technical and socio-economic setting.” (Food and Agriculture Organization of the United Nations, 1985).

“In the context of rainfed agriculture, a land utilization type refers to a crop, crop combination or cropping system with a specified technical and socio-economic setting.” (Food and Agriculture Organization of the United Nations, 1983).

“A land utilization type [in forestry] consists of a technical specifications in a given physical, economic and social setting” (Food and Agriculture Organization of the United Nations, 1984).

7.1.1.7. Land Use Requirements (LUR)

A Land Use Requirement (LUR) is a condition of the land necessary for successful and sustained implementation of a specific Land Utilization Type. Each LUT is defined by a set of LURs. They are the ‘demand’ side of the land land use equation: what the use requires of the land. You can think of the LUT as ‘requiring’ certain general properties of land; these are the LURs. They are at the same level of generality as Land Qualities (below).

For example, plants require water in order to grow; this might be called the ‘moisture requirement’. The soil must be maintained without chemical degradation, this might be called the ‘avoidance of salinization’ requirement. LURs can be assembled into understandable groups, e.g. ‘crop requirements’, ‘management requirements’, ‘conservation/environmental requirements’.

7.1.1.8. Land Qualities (LQ)

A Land Quality (LQ) is “[a] complex attribute of land which acts in a manner distinct from the actions of other land qualities in its influence on the suitability of land for a specified kind of use” (Food and Agriculture Organization of the United Nations, 1983).

“A land quality is the ability of the land to fulfill specific requirements” for the LUT (van Diepen et al., 1991) for each LUR there is a corresponding LQ. Land qualities are the ‘supply’ side of the land land use equation: what the land can offer to the use. In some sense, this is just a semantic difference, or a different point of view, from the Land Use Requirements.

For example, the land can supply a certain amount of water to the crop, this might be called the ‘moisture availability’ Land Quality. On the other hand, the crop has a requirement for water; this ‘moisture requirement’ Land Use Requirement corresponds to the ‘moisture availability’ Land Quality.

Land Qualities are usually complex attributes of the land, i.e., they can’t be directly measured or estimated in routine survey. This is as opposed to Land Characteristics (see next), which are directly measured or estimated. Therefore, LQs must be inferred from a set of diagnostic Land Characteristics, with a variety of analytic methods. Land Qualities act more-or-less independently to affect suitability. This is to avoid a proliferation of LQs in the evaluation. In practice, LQs may interact (e.g., moisture availability and soil fertility) but much of the complexity is avoided by abstracting from Land Characteristics to LQs.

7.1.1.9. Land Characteristics (LC)

Land Characteristics (LC) are simple attributes of the land that can be directly measured or estimated in routine survey in any operational sense, including by remote sensing and census as well as by natural resource inventory. Examples: surface soil texture and organic matter, current land cover, distance to the nearest road.

In general, the effects of a LC on suitability are not direct, but through their effect on land qualities. This is because a single LC may affect several qualities often in contradictory ways, e.g., sandy soils may have low fertility and water holding capacity, but may be easy to till and there are no problems with aeration of the roots.

Here the soil texture is the LC, the others are LQ. This first step to resource inventory is to map the land units or natural resources unit. These units are based on the various factors of land qualities. Land qualities are derived from the land characteristics. The next step is to find out the land use requirements. Land use requirements are depends on the aim of the project as well as land utilization types. The following section describes the procedures of land evaluation.

7.1.1.10. Criteria for the selection of Land Use Requirements

There are four criteria by which we can select LURs: (1) importance for the use; (2) existence of critical values in the study zone; (3) availability of data with which to evaluate the corresponding LQ; and (4) availability of knowledge with which to evaluate the corresponding LQ. Let us discuss the criteria in detail.

(i) Importance for the use

The Requirement must be important for the use, or it is omitted from the analysis. Here is where a careful definition of the LUT will repay the effort.

Importance can be rated ‘very important’, ‘important’, or ‘not important’.

For example, harvest requirements are irrelevant to pasture lands; mechanization requirements are irrelevant to LUTs with only human or animal traction.

(ii) Existence of critical values in the zone

Existence of critical values can be rated ‘frequent’, ‘infrequent’, or ‘none’.

For example, although mechanization requirements are important for mechanized agriculture, in a given zone there may be only level, easily-trafficable, medium-textured, stone-free soils, presenting no limitations to mechanization. In this case, mechanization requirements would not be included in the evaluation.

(iii) Availability of data with which to evaluate the corresponding LQ

Even an important LUR with differences in the corresponding LQ cannot be included in the evaluation if there is not sufficient land data on the diagnostic LCs, which would be used to evaluate the LQ.

Examples: The LQ ‘moisture availability’, in the absence of reliable long-term climate records and moisture release characteristics of representative soil profiles; the LQ ‘erosion hazard’ without measurements of rainfall intensity, without a slope map, or without information on topsoil particle size distribution and surface sealing characteristics.

Data availability can be rated ‘available’, ‘not available but obtainable with survey’, or ‘not obtainable’. If ‘obtainable with survey’, an estimate of the cost/benefit of surveying must be included. New surveys may be impractical within the time or budget of the evaluation.

It may be possible to use a surrogate set of LCs, if the desired LC is not available. In the example above, perhaps natural vegetation type might indicate moisture availability. But at a certain point there is not enough precision, and the data availability is rated ‘not obtainable’.

(iv) Availability of knowledge with which to evaluate the corresponding LQ

A LUR cannot be included if there is not sufficient knowledge on the relation of diagnostic LCs to the corresponding LQ. This motivates applied agricultural (etc.) research.

Knowledge availability can be rated ‘available’, ‘not available but obtainable with research’, or ‘not obtainable’. If ‘obtainable with research’, an estimate of the cost/benefit of the applied research must be included. This is almost always impractical within the time or budget of the evaluation.

For example, the LQ ‘risk of compaction’ (due to mechanization) is a very important LQ in the western plains of Venezuela; however there is no agreement on what measurable LCs can be used to predict this risk, so it has to be omitted from land evaluations.

7.1.1.11. Matching tables

These are also called ‘maximum limitation’ tables. They are in the form of a matrix, with the rows being the different diagnostic LCs, the columns being the (classified) LQ ratings, and the cells being the value of the diagnostic LC (row) that must be met or exceeded in order for the LQ to be rated in the severity level indicated by the column. Thus, matching tables limit the land quality rating to the most limiting value of the set of diagnostic land characteristics.

Advantage: simplicity, easy-to-understand graphical presentation.

Disadvantage: can’t account for interactions between diagnostic LCs (this is a serious disadvantage).

To use the table, start at the upper left and find the column corresponding to the LC value for the evaluation unit. The LQ rating is provisionally this column’s heading. Now, move down one row and find the column corresponding to the LC value for the evaluation unit. If the column is the same as, or to the left of (less limiting than) the provisional rating, keep the same provisional rating. If the column is to the right, move to that column, which now becomes the provisional rating. Do the same for each row; at the end of the process, the provisional rating becomes the final rating, since all diagnostic factors have been included. Another way to use the table is simply to find the column corresponding to the LC value for each row, and then use the right-most column as the final rating.