The following five sections present more than thirty survey techniques, grouped under twenty-five sub-headings. In addition, a total of twenty-four examples is given in this manual. Most of them are drawn directly from field experience. Land use, land capability and suitability surveys are fundamental for rationalizing land use in a watershed. Following are descriptions of five basic surveys:. Soil survey needs will have to depend on whether or not there are existing data available.
If a standard soil survey has already been undertaken, only some supplemental data will be required. If no such survey has ever been undertaken, there will be a need for a new survey. When soil information is lacking a new survey must be undertaken. For watershed conservation, the main objective of survey is to provide basic information for land capability classification, and therefore, the survey may be of a relatively simple nature. Such a survey usually includes: identification of major soil types and their boundaries; recognition of problem soils; information on soil depth; and identification and location of limiting factors, e.
If the survey is for land suitability classification, further information on soil nutrients, moisture and root zone conditions, as well as on economics, etc. Soil survey manuals and guideline books of FAO should be consulted. Example 1 provides simple guidelines for a soil survey of a watershed in northern Thailand.
The work was done by university students under a government project supported by FAO. The field survey, covering a total area of 42 ha was completed in man-days. A final report and a scale map were produced soon afterwards. The objective of the survey is for land capability classification using the "Treatment-oriented system" see Appendix 2. Even if a standard soil survey exists, a supplemental survey may still be needed.
For instance, soil depth and soil limiting factors are vital to land capability determination yet they may not be shown sufficiently on the existing maps due either to the scale of the map or the nature of the original survey. Also, soil boundaries will need to be re-checked because standard soil surveys usually concentrate on agricultural lands rather than on watershed slopes. Slope analysis is an important step towards rationalization of land use in a watershed.
It provides the basis for land capability classification, land use planning and soil conservation needs. The "Circle Interception Method" which can be done by office clerks with little training is explained in Example 3. A circle is used because it has equal distance in all directions and hence represents a fixed horizontal distance on the ground.
By overlaying a contiguous circle sheet on a topographic map and counting the contour intervals in each circle, one can get the values of the vertical rise. The diameter of the circle depends on the map scale and contour interval.
Too big a circle will represent too great a distance on the ground whereas a circle which is too small will make the work impractical. Diameters of 8 mm to 11 mm have been used satisfactorily on and scale maps respectively. Slopes can be grouped into many categories. As a rule, slope categories should be the same ones used in the land capability classification.
Each slope category should be assigned a number or a letter and given a colour for mapping convenience. Example 3 shows the techniques for slope analysis and mapping. The purpose of this brief soil survey of the project area approx. Major soil groups of the project area should be identified and the boundaries of each marked on the map.
To find their boundaries the following procedures can be used:. The following soil limiting factors should be looked at closely in addition to the major soil types:. Soil depths can also be observed along road cuts, stream banks and housing sites. Usually, for the same type of soil, depth measurements should be made at the changing of topography i. Neither soil depths nor other soil data are needed on alluvial soils. A simple recording form should be made according to this guideline and to be used in the field. Some reference information may be included in the form, for example, site grid reference , vegetation, topography, etc.
The sequences of labels on the soil maps are suggested as follows in each mapping unit:. When soil is less than 90 cm, use auger to measure and mark soil depth class on this sheet and the actual depth on map. Jamaica has completed a Soil and Land Use Survey covering the whole island. The reports were issued intermittently by the Soils Department of the Regional Research Centre, University of the West Indies, Trinidad, on an irregular basis since The soil classification system used in these surveys was rather simple and conventional, compared with the international soil classification systems now existing.
Its advantage was that it was based upon almost entirely physical characteristics texture, structure, colour, depth, drainage, moisture retention, etc. The present purpose for producing a soil map is mainly for land capability classification. The Project feels that the existing information can be largely used.
Some supplementary items such as soil depths, land use limiting factors will have to be collected in the field. Therefore, taking account of the time constraint, it was decided to use the existing maps as a basis for preparation of a new one. Before going out to the field, all available reference material and aerial photographs were gathered and studied.
Sometimes, a general observation in the field was required. The procedures were:. However, the maps attached to the Parish survey report at a scale of are the basic material for producing soil maps covering the project area. The boundaries suspected of being inaccurate were also checked using aerial photographs provided by the.
It was found that, in general, there was estimation of the river wash and an underestimation of the limestone areas. These should be corrected. Soil limiting factors taken into consideration where stoniness, occasional flooding, waterlogging and severe erosion hazards. The final soil map was drawn at a scale of Since the final soil map was allowed to produce in a period of two to three weeks for each unit watershed, it was impossible and undesirable to have great precision and detail. It is important to note that the accuracy of the prepared soil map will not exceed that of the existing map drawn at a scale of especially regarding soil types and their boundaries.
The most important elements for this type of map, however, are soil depths and limiting factors. Finally, statistics were prepared, giving the acreage covered by each soil type or mixture of soil types in the area. This was done by cutting out the different areas of each soil type and weighing them against a reference square of known acreage. The main objective of slope analysis is to provide the basis for land capability classification and for planning of proper land use and soil conservation treatment.
The importance of slope analysis cannot be over-emphasized since this is the first step towards rationalized use of watershed slopes. Many methods are applicable for such analysis: airphotos; slope models; even digitized computers. However, judging from resources available and the manpower conditions in the developing countries, the "Circle Interception Method" is probably most suitable. A linear line is established on a piece of grid paper between the intercepted contour intervals and slopes:.
The slope is divided into seven classes and then each line is extended to meet the linear line mentioned above. Using the linear line as an axis, the relation between slope classes and the corresponding contour intervals is obtained. However, the procedure to produce a graph is the same. Slopes are divided into seven categories or classes in line with the land capability classification criteria. Each class is assigned a colour. One circle on the map equals 1. With the surrounding area of 0.
The smallest area of 1. Since the circle's diameter represents feet 76 m on the ground, the slope thus obtained was the average of that distance unless in some occasions two slopes were analysed in one circle. All the sheets should be mounted in a consistent manner in one watershed. Special attention should be given if there are two slopes ridge or valley, etc. First read horizontally according to the contour intervals counted from the circle.
When this meets the linear line, read down to get slope category or class. A record should be kept to see the accuracy of the work. If low accuracies less than 90X are found, the analysis work of that sheet should be re-done.
These points should be accessible, easily recognizable and well distributed if possible. Any draughtsman or person with little experience can be trained to do this kind of analysis work. According to experience, after several days to one week of training, a person could complete about circles an hour. Based on a five-hour working day, 2 circles or an equivalent of 2 acres 1 ha on scale map can be completed each day. A small watershed of 25 acres 10 ha can be completed in two weeks time or in ten working days with a two-man team.
Slope analysis can also be done by using air photographs and stereovision. The photos are first aligned. Specially designed 'slope scale models' are placed on each print and rotated until a sloping dotted line fits the slope to be measured. The angle between the two dotted line is read to determine the actual slope on the ground. The principle employed is that of a variable parallax wedge. It needs an experienced photogrammetrist to do a satisfactory job.
Land capability and suitability classification are the foundation of proper land use. Many classification criteria have been developed since the first one was introduced in s by the Soil Conservation Service of the United States. Although capability and suitability are sometimes exchangeable, the former's primary consideration is to prevent land degradation and the latter is to consider the fitness of a given type of land for a defined use FAO, a. For hilly watersheds, a "treatment-oriented" classification has been used successfully in many developing countries since the s.
The characteristics and usage of this classification can be briefly described as follows:. When a third factor, soil limiting factor, is present, the land is classified as suitable only for less intensive use. All these factors can be measured or seen on the ground and the process and results of classification can be easily understood by field assistants and farmers. A piece of land which cannot be treated with prescribed conservation measures should not be used for cultivation or orchards. It is permissible for less intensive use but not for over-use.
It can also be applied readily at the farm level by a field assistant using a hand level to measure slopes and a soil auger to examine soil depths. Appendix 2 shows the classification in a summary form. A detailed report can be seen from Sheng Example 4 illustrates the procedures for producing a land capability map using this classification system. Figure 6 shows the mapping procedures for producing this type of land capability map and thereafter a land use adjustment map.
The procedure is for developing a map based on the treatment-oriented land capability classification system for classifying steep upland watershed! Other limiting factors i. Any land which is over 30 degrees or below 30 degrees untreatable should be classified for other purposes i.
Use within its capability and lower use are permissible but use beyond its capability should be discouraged. Land suitability classification is the process of appraisal and grouping of a given area for a specific kind of land use FAO, a. Economic considerations, among others, are strongly involved in the determination of suitability. There are several levels of classification according to actual needs for finding varying degrees or categories of suitability.
The four categories are as follows:. There are two orders represented in maps and reports: S suitable and N not suitable ;. For instance, S1 highly suitable , S2 moderately suitable , S3 marginally suitable , N not suitable , etc. To determine the class, economic assessment is needed, i. The units differ from each other in their production characteristics or management requirements.
The criteria used can be qualitative or quantitative. Also, the classification can be applied to the current use or potential use. A piece of land can be classified into many objectives according to the needs. Suitability criteria for rainfed agriculture, irrigated agriculture, or forestry can also be seen from FAO publications b, , and b. Present land use and cover type surveys are also fundamental to watershed management. Before beginning this type of survey, several important factors must be predetermined:. An example is given with the present land use map page 66 ;.
Example 6 shows some details in obtaining aerial photographs, survey procedures and mapping, under a FAO project in Jamaica. Using computers with image processing techniques and Geographic Information Systems GIS can also produce this kind of map. Explanations can be seen in Appendix 3. The project contracted a Canadian firm to do aerial photography. A brief description of photography and photos are as follows:.
These points were scattered over the project area and some were outside but close to the watershed boundary. After selection, the final prints of natural colour were obtained in May in two kinds of colours. The black-and-white set was for producing contour maps. The photo-interpretation work was done in July and August The procedures were as follows:. Delineation of land use patterns was done with a rapidograph pen.
Usually after a day of delineation in the office, the following day was spent on field checking. The smallest unit delineated on photos was 5 mm by 5 mm or about 1. Mixed crops which cannot be seen from the air photos created some difficulty in identification and delineation. Therefore, only the apparent mixtures were interpreted. The present land use map indicates various types of information, pertaining to land use at time. However, the accuracy and effectiveness of this map, is dependent on several factors, namely:. These are controlled mosaics produced from the same photos mentioned above.
The line should be thin and lear. It is best to use a rapidograph pen 0. Land use adjustment survey is essential for further planning of proper use and conservation needs. Under-used lands, especially those which are state or community owned, could be used for settlement or development purposes. Land which is currently used within capability limits may still need soil conservation treatments to ensure its perpetuity.
In obtaining such information, first consideration should be given to the land use policy of the government. For instance, whether or not natural forests present use on potentially cultivable lands are considered to be under-used lands and subject to intensive use or for settlement when required. Each use type should consequently be considered against each capability class to rate its degree of over-use, under-use and within-capability use.
After the proper criteria are determined, a map showing land use adjustment needs can be produced by overlaying a present land use map on a land capability map of the same scale see Fig. The list of criteria and a land ownership map should be kept on hand in the mapping process. Example 7 shows the mapping procedures, a criteria list together with a sample map for reference.
The map shows the sites and areas of the use conditions. It only indicates the needs of adjustment; any adjustment and conservation plan should depend on further planning actions see 8. Nevertheless, this map will make further development planning much more easy and objective. The land use adjustment map is produced by overlaying a present land use map on a land capability map.
It contains information on use conditions such as over-use, under-use or use within capability but needing soil conservation treatment, etc. A classification criterion for determining land use conditions was first worked out. This was produced by comparing present. Soil erosion is a major watershed problem in many developing countries.
In a watershed there may be many different sources of erosion. The main source areas should have been identified during preliminary investigation stages once identified, a detailed survey should be implemented using criteria and forms developed according to local needs. The main objectives are to pinpoint main erosion sites, define their extent, study their causes and, most importantly, suggest possible corrective or rehabilitation measures.
The survey should be management-oriented rather than academic-oriented. Air photo interpretation plus field checking should generally be sufficient for most erosion surveys. In the following sections five erosion-related surveys are briefly described:. Geology and geomorphology of a watershed have significant indications on the fluvial processes of channels and hillslopes and erosion rates.
In many countries, geological maps and information may be already available. However, the map scale may often be small and the information is not specific enough to cover the watershed in question. Some rechecking and refinement are usually needed. If there is no existing information, a brief survey is required. However, the watershed manager should spell out what major data are needed from management point of view and not ask for a general survey which may include unwanted information and take too long a period to complete.
The basic geologic information needed is related to erosion and sedimentation. Rock types, depth of weathering, structures, among others, are the main concerns. For identification of erosion hazards and slope stability, further information should be provided on:. Geomorphology deals with land forms in a watershed. The fluvial processes of channel development and hillslope evolution are the main concerns for a watershed manager. A survey of land forms will result in a better understanding of the erosion process, hazards, and hence of the management possibilities.
For instance, a valley at youth stage will have more active erosion than one at old stage. Hummocky topography at the base of a hill is characteristic of landslide topography. High stream density usually means quick surface runoff and flash floods, etc. This kind of information, together with rock types and structures, permits proper selection of sites for dams and roads as well as estimation of peak flows and timing, etc.
In addition to collection of descriptive land form information, there are some quantitative analysis methods which can be used for comparison or interpretation. With a reasonably good topographic map there should be no problem in implementing such an analysis for a watershed. Sheet erosion data may be obtained in several different ways; the determining factors will be time, expenses, and existence of data:. Investigation should be carried out carefully and collect as much evidence as possible;. Care should be given to the validity of equations or models when they are used on steep slopes;.
The survey of sheet erosion can be conducted in conjunction with soil survey. Erosion information can simultaneously be shown on the soil map.
Example 8 shows a classification of sheet erosion by water used in the USA. Gullies are comparatively easy to identify on air photos. However, field checking is still needed to ensure proper interpretation. Accurate measurements of gully development head and channel need bench mark setting and ground surveying. Whether this is desirable at the planning stage depends on time and resources.
Gullies can generally be classified by their stage active or inactive , by their form continuous or discontinuous , by their shape V-shape, U-shape, etc. Example 8. Class 4: The land has been eroded until it has an intricate network of moderately deep or deep gullies. Soil profiles have been destroyed except in small areas between gullies. Source: U. Soil Conservation Service. Road erosion is a major watershed problem. Especially in mountainous countries, improperly constructed and poorly maintained roads often contribute large quantities of sediment to downstream areas through side-slope sliding and road foundation failures.
A survey of road erosion should concentrate on three parts: 1 cut slope, 2 fill slope, and 3 road surface and side ditches. During the survey, the site, problem and magnitude should be analysed and possible control or corrective methods be considered. At the end of the survey, the quantity of various control measures should be estimated.
By multiplying each with a unit cost the total cost estimate can be worked out. Example 10 shows a survey form for reference.
Landslides are mostly caused by natural factors, i. However, in many countries, as development takes place in upstream watersheds, the hazards and damages of landslides also increase. Landslide prevention and rehabilitation therefore becomes an important watershed task. A landslide is a downward movement of a land mass from a slope. The major landslide forms are fall, slide, slump, flow, creep and their combinations. Many classifications of landslides have been developed; some depend on material and movement, others depend on causes and still others depend on mechanics and age, etc.
A local classification can be developed according to actual needs. Whatever the classification system, it should be practical for watershed management purposes. The following are some points for consideration:. Major survey activities should involve photo interpretation, field checking, recording and mapping. After considering treatment needs and corrective measures for each slide, a cost estimate should be produced. Example 11 shows a landslide classification and investigation form based primarily on "immediate causes". Streams usually reflect watershed conditions and respond to major hydrologic events.
When the natural equilibrium is lost in a watershed due to people's excessive activities or extremely heavy rains, the stream below will display significant bank cuttings, scouring or sediment deposition. While man can hardly control natural events, efforts to protect the watershed will normally result in less erosion in the streams. Stream erosion surveys can also be done by air photo interpretations and field checking.
In addition to watershed conditions, three items for immediate consideration are bank cutting, channel stabilization and sedimentation. Streams can be classified according to degree or seriousness of erosion in order to determine treatment priorities. Example 12 gives a classification system originally developed by the US Forest Service and modified to suit other countries where more serious stream erosion exists. For streambank protection and water quality control, sometimes a protection belt along streams is needed. To establish the belt needs a survey of present conditions and use. Example 13 gives the width required for the belt on various slopes.
In highly developed or heavily populated watersheds, torrential mountain streams often cause heavy damage to the nearby villages and downstream areas. These streams having steep gradients, extreme fluctuations of flows and massive bedloads are very dangerous and unstable if not controlled. Techniques for torrent control surveys have been well developed and extensively used in Europe, Japan, and many other countries where villages, hotels, or recreation areas are situated in mountain watersheds.
In wildland watersheds or at different socio-economic conditions of less developed countries this kind of work may seldom be practised due to the relatively high cost. Control measures should not only cover streams and adjacent areas where damages may occur but also include the respective tributaries where the torrents start. Control measures usually include vertical and horizontal channel stabilization, bank protection, control of tributary gullies and slides, and revegetation.
Class 0: Stream shows no signs of erosion or excesive discharges. Banks well vegetated, often overgrown with woody vegetation. No recent debris or flotsam on banks or lodged in vegetation. Streambed formed of shingle or cobbles, weathered and often discoloured by algae. Pools well developed. Class I: Signs of incipient erosion. Banks undercut and raw in places; fresh sand and sediment in pools; sand-bars active; streamside vegetation may be gone or disappearing.
Class II: Accelerated erosion evident, sand bars active, gravel and rocks scoured clean, pools filled with sediment. Streamside debris and flotsam deposited on soil and vegetation well above banks. Some tributaries gullied and depositing fans or deltas in main stream. Class III: Severe erosion.
Same symptoms as Class II. Stream bends cutting out actively; bottomland being lost by bank cutting; stream turbid or carrying bedloads most of the time. Class IV: Very severe erosion. Extremely active bank slides and cutting; heavy deposits of fresh bedloads; torrent nature of flows. In any watershed, there exist many kinds of natural resources: water, soil, forest, range, wildlife, etc.
Depending on management objectives, many basic surveys or investigations of these resources are needed from which better management plans can be prepared. In the following sections, brief descriptions of five survey techniques relating to natural resources are given:. Climatic surveys usually concentrate on items such as precipitation, temperature, evaporation, humidity and wind, etc.
Most of the data can be collected from climatic stations in a watershed or from stations nearby. However, some compilation and analysis work is usually necessary. The basic information may include the following:. If there is no such data available, new stations need to be set up. In addition to usual precipitation measurement, some stations may need basic instruments as shown below:. Rainfall data is probably the most important factor relating to water resources, crop production, runoff and erosion. Three methods are usually used for estimating average rainfall in a watershed.
They are 1 arithmetic mean, 2 Thiessen polygon polygons are formed from the perpendicular bisectors of lines connecting nearby stations , and 3 isohyetal method. Example 14 shows how to apply these methods. For rainfall intensitites, data from automatic raingauges should be used and analysed. A hydrologist or a textbook should be consulted to obtain intensities at different time periods and frequencies. If the only data available are daily rainfall, the following equation can be used to find intensities of various short durations:.
The constant, 0. This exponent can be modified to fit local conditions and for different return periods.
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For most developing countries, the important items in hydrological surveys are streamflow, runoff and sedimentation. Water quality may also be important in some countries. The data required on streamflow and runoff are: a peak or flood flow for designing engineering structures, b low or minimum flow for estimating water supplies and c annual total and its variation for various planning and design purposes.
Three major conditions may exist for such surveys. The first one is that there are already stream gauging stations established in the watershed with years of records. In this case, work is limited to compilation and analysis. The second condition is that there are some gauging stations in downstream areas or in neighbouring watersheds. In this case, two methods can be used, given that the gauged watershed and the ungauged one under study are similar in climatic and biophysical conditions:.
Geological Survey should be consulted. The third possibility is that no gauging stations exist in the same region and therefore no data are available. In this case the following analysis is recommended:. More accurate measurement can be done by using a current meter. On wide streams, many horizontal sections should be divided for individual readings. Once the average velocity is obtained, multiply it by the cross-section to get Q;. Especially for small engineering structures and local floods this equation should be considered appropriate:. Other free and widely available tools could be used ranging from highly scalable — if more challenging to learn — tools such as R and R Studio and more limited but familiar tools like spreadsheets.
Other easy-to-use tools for creating map-based visualisations are also available. A press publishing OA monographs may have many different motivations and needs with respect to analysing and using data about books. These range from tactical issues of whether to invest time in social media promotion, or in hosting OA content on multiple platforms, to large-scale strategic questions of the balance of a title portfolio and its evolution.
In our study we simplified these into three questions:. The data available provided useful insights into the three questions we asked in this study. We also identified relatively simple steps that presses can take to increase the richness of the data available to them, and the level of insight it can provide. These include using tagged social media links in promotion campaigns, and providing authors with tagged links they can use when promoting their own books via social media. Ensuring platform partners are aware of the value of granular usage data for presses is also important: monthly download figures are less useful than daily, or even hourly, download data.
The data arising from digital distribution of OA monographs presents real opportunities to better understand how people find and access HSS books, and the most effective strategies for widening reach and impact. Readily available data has the potential to help publishers understand how individual titles are performing, where scarce promotion resources might best be deployed, and how a press is performing on its social mission. The challenges of making the most of this data are real; finding the resources to capture, manage, and engage with data that arrives in different formats may be especially daunting for smaller presses.
However, these challenges need not be insurmountable. Some university-based OA presses may be able to engage more effectively with data by working with campus partners including the library and IT department. For others there may be value in exploring the formation of cooperatives with like-minded or complementary presses in order to gain access to economies of scale associated with tools and strategies for gathering and presenting usage data from a range of sources.
Because real strategic advantages are available for those that engage with the opportunities, continued investment in the development of shared infrastructure needed to support a vibrant OA monograph landscape will be key to ensuring that small OA monograph presses are able to make the most of increasingly rich data landscapes. She is also Director of Research for Knowledge Unlatched Research: a close-knit team of researchers and publishing industry practitioners working together to help realise the possibilities of digital technology and open access for specialist scholarly books and the communities that care about them.
He has been a biochemist and a technologist, worked in scholarly publishing as an advocate for open access, and now focuses on studying the changing cultures and institutions of the academy. He is also a technical advisor to Knowledge Unlatched Research. His research interests include online identity, social media, digital death, infancy online, mobile gaming, and the changing landscape of media distribution. Click here to cancel reply. Email Address. Subscribe to the Impact Blog. This work is licensed under a Creative Commons Attribution 3. Maximising the impact of academic research.
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Why is data a challenge for OA monograph publishers?
What kinds of data are available to OA monograph presses? In our study we focused on: Download statistics made available by platforms and repositories hosting books Google Analytics data Social media data We cross-referenced this against key date and promotion information provided by the press; dates of book reviews published in major news outlets, or the launch of a MOOC relating to a title, for example. How did we gather and interpret the data?
What kinds of questions did we ask of the data? In our study we simplified these into three questions: How is this book doing?