FAO E-workshop "Land-Water Linkages in Rural Watersheds"
Discussion Archive
Referring to Session 2:
Assessing and perceiving land–water linkages

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This intervention addresses session 1 in general, and questions 4, 5 and 10 in particular.

Dear participants of the electronic workshop on land-water linkages in rural watersheds,

[5-1] as you all know, the workshop has started on Monday. Until now it is still rather quiet. I assume this is due to your intensive reading of the excellent background material which was compiled by the workshop moderators. I think it is a very good and timely initiative of the Land and Water Development Division of FAO to hold such a workshop and I am impressed by the number of registrations from all over the world. I hope there will be a lot of interesting discussion and sharing of experience over the next weeks. There is large scope to contribute experiences, to critically comment on the many statements which are made in the background and discussion papers as well as in the case studies.

[5-2] Although I have not yet managed to read through all the background material available for the workshop I would like to throw some provocative statements into the discussion. The thoughts base on my work experience in watershed management at different geographical scales in the overall Himalayan region as well as on my present assignment in the sustainable mountain development programme and the coordination unit for the International Year of Mountains at FAO.

Land-water linkages at different geographical scales: how strong is the impact of human activities?

[5-3] Among the questions formulated for the first session I would like particularly refer to items 5 and 6 which were in the center of interest during my work in the overall Himalayan region, and make some provocative statements. The discussion reaches beyond small to medium sized watersheds.

[5-4] The following newspaper headline serves as starting point for my comments:

"The severe floods in Eastern India and Bangladesh are not the result of a natural disaster, but of a ruthless exploitation of wood which has been practised over centuries in the forests of the Himalayas" (Basler Zeitung, 15.9.1998). Such a headline is just one example of many others and makes the following assumptions:

• The forest cover in the Himalaya is rapidly decreasing (which, by the way, only holds true for certain areas, e.g. in the Western Himalayas of Pakistan)
• There is a direct link between forest removal in the Himalayas and flooding in the lowlands of the Ganga and Brahmaputra river systems
• The mountain people with their forest management practices are responsible for the inundations in the plains, a politically highly sensitive statement.

[5-5] In spite of a number of publications on recent studies there are a lot of misconceptions floating around these complex issues. The newspaper statement reflects the still widespread wrong assumption, that land-water linkages identified in small and medium sized watersheds can just be extrapolated to large watersheds. In many studies it can be documented that in small watersheds (<5000km2) the human impact on land-water linkages is dominant. In medium sized watersheds (5000-20,000km2) it is already difficult to distinguish between man made and natural impacts on the land-water linkages. In large watersheds (>20,000km2) natural factors (heavy rainfall events, deep landslides, etc) clearly are the main factors influencing land-water linkages. Such a statement means that land use practices in the Himalaya do not seem to have much to do with flood processes in Bangladesh.

[5-6] Of course, there is a significant contribution of "base flow" from the highland catchments of the Brahmaputra and the Ganga to the floods, but this input is just one element of many others and for sure not a flood triggering one. This in turn means that forest clearing, abandonment of grazing lands or inappropriate agricultural practices in a highland watershed might have disastrous consequences in terms of soil erosion, increased surface runoff and flood flow in that particular watershed (small scale effect) but that this impact is levelled off further downstream (large-scale effect).

[5-7] Finally this means that big projects in upland areas such as afforestation programmes should be realised to improve the ecological conditions of and the livelihood opportunities in the mountain areas themselves, but not with wrong expectations of preventing floods in the lowlands! We are convinced, though, that further efforts are needed to clarify or eradicate misconceptions regarding land-water linkages at different geographical scales. A further clarification of these issues might smoothen political discussions in international river systems and might assist mountain communities to develop or maintain sustainable land use strategies and practices.

[5-8] This contribution is a very pronounced one, many of you might disagree with certain statements or might want to differentiate or modify them based on your own experiences. You are most welcome to do so, a critical discussion of these findings would be very interesting and useful. It would of course be particularly interesting to learn if this differentiation of land-water linkages according to scales as discussed for the Himalayan region is similar in other mountain areas of the world. I am looking forward to a critical exposure and discussion of these ideas.

The complexity of land-water linkages: a big challenge

[5-9] It is obvious that the land-water linkages in rural watersheds are very complex: there are different types of linkages, these linkages differ according to scales, they need to be differentiated into man-made and natural impacts and finally they differ according to agro-ecological zones and socio-economic conditions. Complexity usually implies that it is difficult to get an overview. However, "users" of scientific results (planners, decision makers, politicians, etc.) need clear, synthesised and to the point answers to ecological questions. Apart of a critical discussion of the issues, one useful output of this first conference session could be a synthesis of the present understanding and categorisation of land-water linkages and the identification of gaps. Which workshop participants would take the challenge to create such a synthesis, on maximum 2 pages, with graphs, arrows, boxes or whatever? Maybe the workshop moderators could even think of a competition for that with nice prices for the winners, e.g. a land-water T-shirt? This sounds like a joke, but the effort to synthesise these linkages in a short, clear and graphically attractive form would be a really useful exercise.

The electronic workshop on land-water linkages in the framework of the International Year of Mountains

[5-10] You might all be aware of the fact that, based on a proposal of the Kyrgyz Republic, the UN General Assembly has declared 2002 as the International Year of Mountains (IYM). This decision offers a good opportunity and exciting challenge in the follow-up to Chapter 13 (Sustainable Mountain Development) of Agenda 21. It provides a unique platform to reinforce the long-term process started at the United Nations Conference on Environment and Development (UNCED) in Rio of raising public awareness and ensuring adequate political, institutional and financial commitment to concrete action for sustainable mountain development, hopefully well beyond 2002. FAO was assigned the lead agency role for the IYM.

[5-11] One of the main objectives of the IYM is to increase awareness of, and knowledge on, mountain ecosystems, their dynamics and functioning, and their overriding importance in providing a number of strategic goods and services essential to the well being of both rural and urban, highland and lowland people, particularly water supply and food security. The ongoing electronic workshop and each of your messages will significantly contribute to this important objective. I hope you will be very active in the workshop and share your thoughts with the other participants!

Please visit the website of the IYM:

English: http://www.mountains2002.org
French: http://www.montagnes2002.org
Spanish: http://www.montanas2002.org

Selected bibliography:

HAMILTON, L., 1987: What are the impacts of Himalayan deforestation on the Ganges-Brahmaputra lowlands and delta? Assumptions and facts. Mountain Research and Development, 7 (3): 256-263.

IVES, J.D., MESSERLI, B., 1989: The Himalayan Dilemma. Reconciling development and conservation, 295 pp. Routledge, London.

KUSTER, H., 1993: Dynamics of forest cover in the Indian Himalaya: an investigation in the upper Beas catchment (Kulu-Valley, Himachal Pradesh). In: Messerli, B., Hofer, T., Wymann, S., 1993: Himalayan environment: Pressure-problems-processes. Geographica Bernensia G38, 206 pp. Institute of Geography, University of Berne.

HOFER, T., 1993: Himalayan deforestation, changing river discharge, and increasing floods: Myth or reality? Mountain Research and Development, 13 (3): 213-233.

MESSERLI, B., HOFER, T., 1995: Assessing the impact of anthropogenic land use changes in the Himalayas. In: CHAPMAN, G.P., THOMPSON, M., (Eds): Water and the quest for sustainable development in the Ganges Valley. Global Development and the Environment Series. Mansell, London.

HOFER, T., MESSERLI, B., 1997: Floods in Bangladesh - Process understanding and development strategies. A synthesis paper prepared for the Swiss Agency for Development and Cooperation. Institute of Geography, University of Berne.

HOFER, T. 1998: Floods in Bangladesh: A highland-lowland Interaction? Geographica Bernensia G48, Department of Geography, University of Berne

HOFER, T., 1998: Do land use changes in the Himalayas affect downstream flooding? - traditional understanding and new evidences. Memoir Geological Society of India. No. 41, 1998: pp. 119-141, Bangalore

The author is Forestry Officer (Sustainable Mountain Development and Conservation), with the Coordination Unit - International Year of Mountains, FAO, Rome, Italy

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Dear all,

This intervention relates mainly to questions 11 and 12 and the identification of land-water linkages, in particular question 5.

[26-1] Let me first say how positive to see so many interventions questioning some of the old shibboleths regarding 'land and water degradation'. I have enjoyed Ian Calder's attacks on the myths of forestry in the past [see also background paper 1 for this workshop –ed.], and it is now good to see 'sediment' starting to enjoy the same treatment! While there has been considerable de-mythologising of the degradation 'story' in agriculture and soil and water management circles it has less to receive the same treatment in water circles.

[26-2] In this message I would like to discuss a 'story' related to the myth of the 'poor agricultural practices in the headwaters leading to increased siltation in reservoirs'. The story relates to South Eastern Zimbabwe, the area I describe in case study 19. A major agribusiness user of water in Zimbabwe are the large sugar estates of the 'lowveld'. These estates rely on an extensive series of mid-catchment storage dams, and like so many others of their sort 'sediment' is their great bugbear. That the 'increased' sediment is blamed on the poor farming practices, deforestation, over-grazing etc. etc. of the 'indigenous', 'subsistence' farmers of the headwaters will come as no surprise.

[26-3] Following the devastating drought of early 1990s some of the sugar estates started outreach programmes to work with the farmers in the headwaters to 'improve' their land management. By the late 1990s those involved in the outreach programme were reporting positive results - the suspended solids entering their dams were decreasing dramatically - a simple open and shut case? Not really - the outreach programme was tiny, and the catchment area large (1,000s of sq. km). To a disinterested observer it seemed highly unlikely that changes in how the headwaters were managed could have been responsible for these dramatic falls in sediment load. What then had changed, and what could explain the improvement?

[26-4] In Zimbabwe and much of southern Africa, rainfall over the past 100 years or so has been observed to follow a cyclical pattern of above and bellow 'average' rainfall - roughly ten years of above, ten years of below. The patterns may be related to ENSO [El Niño Southern Oscillation –ed.], they may be being intensified by global climate change, they may continue in the future - all that is certain is that they have been observed since records began.

[26-5] The 1970s were by and large a wet decade, the 1980s, however, were one of the driest on record, and were capped in 1991/92 by a total drought over much of the region. Our research demonstrated that this cyclical pattern was reflected in groundwater levels, talking to local farmers suggested it was also reflected in livestock numbers - these build slowly during wet periods, only to crash during droughts.

[26-6] The combination of our research and what we learned from local farmers allows an alternative 'narrative' to that of the cane farmers to be developed. This suggests that during the long dry years, water levels drop, shrubs and grass die, and livestock (before dying) exacerbates the situation by eating everything available, turning the area into a 'desert'. During this period sediment levels generally increase, as what rain does come is un-mitigated by vegetation and can erode easily. In particular large storm events at the end of the dry period can move huge quantities of 'stored' soil. However, once a wetter period is entered, browse and crop cover quickly returns, aided by low livestock numbers, and erosion more or less ceases - waiting until the next dry cycle.

[26-7] Photographs of our study site in the 1990's show a bare expanse of red earth, incomparable to the lush 'humid' vegetation seen since 1994. Sediment that we measured leaving a small headwater catchment where there was no outreach programme and subsistence agriculture was being practised never exceeded 5 tonnes/ha - far from the 70-100 reported from so many plot based experiments.

[26-8] This is a narrative or story (just like for the sugar farmers) - to have 'scientific proof' of it, it would be necessary to monitor sediment loads (and other key parameters) for at least a full 20 year cycle! However it corresponds well to what is known of erosion and how it happens from other arid and semi-arid regions. In some parts of Australia for instance erosion takes place in hundred year events! Set your silt traps in the wrong year and you risk getting some pretty silly results!

[26-9] What are the 'lessons' if any to be drawn from this story? As usual the recommendation to 'do more research' to better understand the 'reality' underlying erosive processes - however this is often unrealistic in terms of the need to do something 'now'. The unpalatable message may therefore be to avoid building dams in arid and semi-arid areas (they are after all in addition to the sedimentation problem hugely wasteful in terms of water lost to evaporation). Large parts of Africa are after all 'erosion surfaces' - erosion is, has been and will continue to be a part of how these landscapes work (just think of the Nile floods and their life giving sediment - before the dam that is!) - expecting sediment loads to be similar to those of northern mountain dams is simply unrealistic.

[26-10] A final lesson that relates both to this story and to the work reported in case study 19 relates to scale. The lesson is simply that the answer to Benjamin's question about whether we should concentrate on the small to intermediate level must be a resounding yes. Land water interactions are only measurable at the small scale - working on minimising sedimentation in the catchment of a micro-dam in a 5 sq. km catchment may be worthwhile - trying to improve land management in Ethiopia in the hopes of seeing a result at Aswan is not. Improving tank maintenance in India will lead to measurable improvements in local groundwater, but will not affect flooding in Bangladesh.

The contributor is Project Officer - Community integrated water resource management at the IRC International Water and Sanitation Centre, Delft, Netherlands

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Referring to intervention No. 26 by Patrick Moriarty I have to report that the forestry myths are still alive and well in some quarters and sustained "attacks on the myths of forestry" may still be necessary. See the recent report relating to the Mekong floods:

Date: Wed, 27 Sep 2000 21:17:40 -0700 (PDT)
From: owner-irn-wcd@netvista.net
Subject: LS: UN agency blames Mekong floods on deforestation

BANGKOK, Sept 22 (Reuters) - A United Nations agency said on Friday deforestation was a major cause of the floods that have devastated Indochina and the Mekong delta in the last month. The UN's Economic & Social Commission for Asia and the Pacific (ESCAP) said in a statement forests in most Asian countries had been reduced to about 25 percent of land area in 1995 from 70 percent in 1945.

Whilst I also feel positive about the new questioning attitude to "land and water degradation" I feel that in the background the "erosion game" still has many players. Stocking (1996) warns us that "scientists are just one set of actors in the 'soil erosion game', a game in which it is advantageous a) not to admit you do not know the answer; b) to make unverifiable assumptions so that, if your answers provide bad advice, blame does not attach to the professionals; and c) to exaggerate the seriousness of the process to gain kudos, prestige, power, influence and, of course, further work".

Reference: Stocking, M. 1996 Soil erosion - breaking new ground. In: M.Leach and R. Mearns (Eds.) The Lie of the Land, Villiers Publication, London. pp.140-154.

The contributor is Director of the Centre for Land Use and Water Resources Research, University of Newcastle, Newcastle Upon Tyne, UK

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As a relative newcomer to watershed issues, I am learning a great deal from this workshop, both the papers and the email discussion. My thanks to the organizers. What follows is mostly a summary of observations from several of the senior soil and water conservation engineers in the Atlantic Canada region. It is relevant (belatedly!) to Session I, questions 2 & 3 and Session II, question 9 of this workshop and possibly also to some of sessions 3 & 4.

[34-1] Since the mid-seventies, soil conservation practices have become an essential element of the potato production systems in the Canadian province of New Brunswick's (NB) Upper St. John River Valley and more recently in Prince Edward Island (PEI). Undulating slopes, excessive runoff, highly erosive soils, soil compaction, stone picking, organic matter depletion, loss of soil available water holding capacity and crop productivity have compelled potato producers to adopt and implement soil conservation systems to ensure the long term sustainability of agriculture. Sheet and inter-rill erosion are being addressed through better rotations, conservation tillage, residue management, mulching, winter cover cropping, crop rotation and strip cropping. On more complex topographical conditions, integrated water erosion control systems such as diversion terraces combined with strip cropping systems and grassed waterways have been effectively implemented, decreasing the incidence of rill and gully erosion on the most sensitive crop land.

[34-2] Various erosion or runoff prediction models have been tested in the region (RUSLE, WEP, etc.). Research plot, farm field and watershed scale research has been underway in the region for over 12 years. It is estimated that from 60% to 70% of the land base currently in potatoes in both PEI and NB is experiencing excessive or unsustainable soil loss as a result of farming the complex and undulating slopes. While the adoption of soil conservation practices has been difficult due to market pressures, farming efficiency, land tenure and land availability issues, producers are becoming increasingly aware of the need to adopt agronomically, environmentally and economically sustainable production systems. Progress is being made, with significant acreages in New Brunswick and PEI now protected with appropriate combinations of soil and water conservation measures in the field.

[34-3] Recent occurrences of very intense rainstorms have heightened public and professional awareness of the environmental issues associated with soil erosion. For example, the increase in potential risks for pesticide contamination of watercourses. Pesticides can and have entered watercourses during intense rainfall events attached to eroded soil particles and may cause local stream fish kills. Also, non-point-source pollution from agriculture is increasingly becoming an important environmental issue at the watershed scale in the region in critical areas such as municipal surface drinking water supplies or lakes. Therefore agriculture in the region must constantly continue to develop and adopt cost effective soil conservation management technologies and strategies. These may need to be better integrated with other pesticide and best management practices in the near future.

[34-4] Do effective soil conservation technologies and strategies now also have to take into account developing concerns for the potential impacts of global climate change? There has been considerable international scientific discussion in recent years about the impacts of emissions of greenhouse gases (GHGs - particularly CO2, CH4 and N2O) on our atmosphere and on global warming. Scientific modeling and measurements suggest that GHG emissions to our atmosphere may be driving global warming and climate change. Predictions are that global warming will have significant impacts on our atmosphere and our climate. The potential impacts of climate change in Atlantic Canada may include increased variability in climate, increased frequency of extreme climate events, local droughts, intense rainfall events, increased soil erosion and runoff, flooding, sea-level rise and coastal inundation. Serious potential environmental and economic impacts of climate change may need to be examined and agricultural adaptation measures considered.

[34-5] However, today's growing challenge with the regional potato industry really still remains the slow rate of adoption of conservation technologies on the land due to limited technical support, unfavourable short-term economics, a lack of long term financial support programs, market pressures, land availability and land tenure. Positive on-farm economics from soil conservation efforts need to be clearly demonstrated. Soil conservationists in the region have noted that the successful adoption of soil conservation systems requires extensive educational and awareness activity combined with on-farm technology adaptation and related cost-benefit information before producers implement the changes. The agricultural industry must play a stronger leadership role in promoting conservation and land stewardship. Regional policy needs and gaps need to be identified and addressed. Our governments must be more aware of the need for more integrated policy instruments, research and long-term programs to address soil and water conservation issues that will produce general societal benefits in the region. (on-field and nearby in-stream benefits, both upstream for the farmers & public, and also downstream ?)

See the ECSWCC Web site for more information on related regional issues: http://www.ccse-swcc.nb.ca

The contributor is soils specialist at the Eastern Canada Soil and Water Conservation Centre, Saint-André, NB, Canada.

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Referring to intervention 29 by Ian Calder -

[35-1] I completely agree with you position about influence of deforestation on flooding. In Russia, during snow-melting, we have high level floods in the taiga areas. I also agree that erosion rates are overestimated for most areas of tropical, subtropical and arid zones. However, the comparison of sediment discharges in a river with mostly undisturbed basins (less than 30% from total area is arable land) and in a river with mostly disturbed basin (more than 70% from total area is arable land) demonstrates that they are 5-7 times higher in the latter case. So we need to define the sediment delivery coefficient for small watersheds with different pathways from agricultural land to the river channels.

[35-2] The example from intervention 26 demonstrates how both climatic fluctuation(as the main reason) and land-use changes influence on erosion rate and sediment delivery. But we still know too little about relationship between natural and anthropogenic factors which are responsible for sediment redistribution within river basins, especially for Asia, Africa and Latin America.

[35-3] It seems to me that it is necessary to develop a well-structured sediment and sediment-associated pollutant redistribution database, which should include the lot of information concerning this problem. As the result, we will have very many "holes" for each study, and we will probably have a clear understanding what we should do in future.

The contributor is professor at Moscow State University, Department of Geography, Moscow, Russian Federation.

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This intervention relates to session 2 in general. Simple farmer-based monitoring of erosion, deposition, soil fertility decline and land use change with a view to aid community discussions

[40-1] Soil erosion has been a matter of public concern for decades in most regions of the world, including references to the Dust Bowl in the US in the 1930s and serious concern over desertification in sub-Saharan Africa, since 1950s and increasingly in the 1970s. As a result, expenditure in some countries has been significant and numerous development projects focusing on soil and water conservation and sustainable use have been supported in most third world countries, especially in mountainous and dryland areas.

[40-2] Rates and the extent of soil erosion have been estimated for many years, largely using the USLE Universal Soil Loss Equation (developed by Wischmeier and Smith, USDA, 1978), and various derivatives, for predicting relative values of sheet and rill erosion from varying land uses and conservation/ management practices, and using wind erosion equations for soil transported by the wind. Such models were widely adapted and developed for use in tropical and other climatic conditions.

[40-3] A direct link has often been made between loss of topsoil and agricultural productivity decline, however scientific evidence surprisingly remains relatively limited. In fact, despite much modelling work and many localised studies to verify estimates of soil loss, the quantification of the problem is not very successful. Apparently, for example, rates of soil erosion were widely cited as above 25 tons/hectare for large parts of the US although estimates of sediment yields (deposited) were in the order of 0.5 - 2.0 tons/hectare, including stream channel and bank erosion! Even today, a wide range of values are proposed from cropland and other land uses. A major problem is that measures usually focus on amount of soil moved and not on amount of soil or nutrients removed from a field or hillside. In fact there is usually substantial deposition of the particles that were mobilised in the air or along the surface, either in the field before reaching a watercourse, or deposited a little further downstream in the stream/river basin.

[40-4] This has increasingly led to the investigation of sediment budgets, linking erosion in upland areas with sediment delivery downstream, often over long periods of time. It has been shown that it is easier to measure soil accumulation/alluviation in a floodplain than to estimate soil loss from the slopes to the basin. In fact visual indicators, such as the extent of burial of root crowns of small trees or shrubs, can be effectively used.

[40-5] Likewise the soil nutrients lost through leaching are not easy to measure as there is a constant flux between the soil solution and the soil matrix to maintain a chemical equilibrium. Thus, nutrients that were removed into the soil solution upstream may be partly taken up or adsorbed into the soil complex (organic matter and clay minerals) lower in the profile or downstream (as a result of runoff and lateral flow). While it may be relatively easy to estimate nutrient content of surface water sources it is not easy to allocate the quantify taken up in different parts of the soil profile or watershed or in groundwater sources.

[40-6] Wide concern has also been raised in many parts of the world that degraded soils allow less rainfall infiltration and storage which is predicted to lead to increased runoff over the land, erosion and flooding. However in many cases land use has also been changing ......maybe partly in response to changing hydrological and climatic conditions in the locality as well as due to pressures and demands to attain higher yields or different products for changing markets. As a result of land use change, more water may be infiltrating or more water being transpired by plants. Visual evidence for decreasing runoff and decreasing flood peaks can also be used, e.g. smaller channels, more stable tributary channels (smaller deposits, more vegetation etc), less frequent and less severe flooding.

[40-7] Another indicator of change in hydrological regime is change in habitat for example reduced habitat for fish and other aquatic organisms, and thus reduced populations of vulnerable species due to poorer quality water, as a result of increased sediment load and stream channel instability, and maybe frequent violent floods. As well as sediment load (suspension and bedload), biological and chemical measures of water quality may be important for instance to show nutrient yield from agricultural land.

[40-8] It would be interesting to hear of cases and methodologies for simple, effective monitoring of erosion and sedimentation and nutrient flux, over reasonable periods of time (in view of variations over the year due to climatic changes and changing land cover) that has enabled to build up a substantial knowledge of what is happening and where, in terms of soil erosion and associated resource deterioration in relation to changes in land use.

[40-9] The results and acquired knowledge, either from systematic use of simple visual and physical measures or from more sophisticated measures, would facilitate and support discussions and further analysis with concerned communities of the effects, implications and costs and benefits in terms of different resource users upstream and downstream.

[40-10] Please let us know of any such monitoring and analysis that you may have been involved in and if possible of subsequent application of the findings through discussions with resource users on changing land use practices or implementing soil and water conservation measures.

[40-11] Where the situation is particularly complex and the effects of land or water degradation severe there has been the use of more accurate and costly monitoring of sediment/erosion balances, including nutrients, through isotopic dating and tracing techniques and high precision remote sensing, which allow to estimate and map the variations across a land area in terms of soil loss and accumulation.

The contributor is Technical Officer with the Land and Plant Nutrition Management Service, FAO, Rome, Italy.

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This intervention relates to session 2, in particular questions 7 and 8.

In response to the request of Intervention 40 by Sally Bunning [regarding monitoring of sediment and nutrient flux]: one of my students recently used farm dams to measure soil and P loss from low-angled hillslopes in semi-arid SW Australia. The work has not been published yet, however, it was presented orally at the IGU Congress in Seoul in August this year.

ESTIMATION OF SEDIMENT YIELDS FROM SMALL AGRICULTURAL CATCHMENTS IN SOUTH-WESTERN AUStrALIA

Julie Throne and Arthur Conacher

ABStrACT

[43-1] Concerns have been raised over the volume of sediments and nutrients entering Oyster Harbour near Albany on the south coast of Western Australia. These concerns led to research on the significance of small, hillslope catchments as contributors of sediment and phosphorus to the main drainage basin of the Kalgan River.

[43-2] The volumes of accumulated sediment in excavated farm dams of known ages were used to estimate sediment yield from 24 hillslope catchments within the main drainage basin. Catchments were selected to reflect a range of environmental factors including mean annual rainfall, slope gradient and soil type.

[43-3] Volumetric sediment yields were converted to mass in order to estimate rates of soil loss. These rates ranged from 0.2 to 3.1 t ha-1 yr-1, significantly less than estimated from a previous study which used caesium 137 in calculating hillslope erosion rates in the same drainage basin as high as 50 t ha-1 yr-1. The sediment yield data were compared with the Langbein-Schumm and other sediment yield curves.

[43-4] Phosphorus concentrations measured in the sediments trapped in the farm dams indicate a fairly high rate of P loss from the small catchments (<0.01 to 2.7 kg ha-1 yr-1) in comparison with the target P loss identified by the Western Australian Environmental Protection Authority of <0.05 kg ha-1 yr-1. The lowest rates of P loss from a catchment occurred where the entrance to the farm dam was surrounded by a large sedge community, highlighting the importance of vegetation as a buffer for waterways.

[43-5] There were no significant correlations between the environmental factors and sediment and phosphorus yields. This indicates the complexity of the relationships amongst the factors in the landscape. The full land-use history of catchments as well as the site-specific factors affecting them must be known in order to understand and explain the movements of sediments and nutrients within the catchments.

The contributor is professor at the Department of Geography, University of Western Australia, Nedlands, WA, Australia.

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This intervention refers to workshop in general.

[44-1] The various interventions have covered many different aspects of land-water linkages in rural watersheds, and provide a wealth of information and ideas. It is my impression that two major issues could be isolated from the discussion.

1. On the one hand, it is clear that we do not yet know enough to predict the effects that certain activities will bring about in a watershed, and that much emphasis is still needed on the monitoring of these effects (both physical and socio-economic);

2. Secondly, there is the question of how to organise people and to assure that most of the stakeholders will be satisfied about the outcome of such activities.

[44-2] With regard to the first issue, it would for example be interesting to know how rivers and streams in the state New Hampshire were brought back to where they were 300 years ago (intervention 32). How was this process monitored and which lessons could be learned from that for other areas? How was the monitoring undertaken of the effects of paddy terraces on streamflow in Japan, leading to subsidisation of paddy production (intervention 14)? And what lessons can be learned from various other forms of long term monitoring, as discussed, e.g. in Russia (intervention 19) and in Zimbabwe (intervention 26) ?

[44-3] Some myths about land-water linkages have already been unravelled (e.g. interventions 4, 11, 26, 29). However, it is clear that more attention should be paid to long term hydrological, physical and socio-economic monitoring in watersheds, or representative sub-watersheds. Maybe all large scale investment programmes in national and transnational (e.g. Niger, Nile) watersheds should spend a small percentage of their costs to such (institutionalised) monitoring activities?

[44-4] The second issue of organising people in watersheds has received also much attention. It is interesting to compare the set-up and characteristics of various types of watershed organisations, as they are established in the USA (intervention 32), India (interventions 15, 21), etc. As mentioned as editor’s note with intervention 31, there do already exist guidelines for water user associations, etc. However, not many experiences have been shared with regard to negotiating platforms for watershed development (intervention 24). Because of the large differences in interests (national security, rural family security and citizen’s financial interests (intervention 32), such platforms are hard to organise and have a difficult task. It is clear that there is still much work to be undertaken in this field, [and it would certainly be interesting to hear of participant’s experience in establishing and working with such platforms! –ed.]

The contributor is associate professor at the Department of Environmental Sciences, Wageningen University, The Netherlands

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As a relative newcomer to the workshop many thanks for the summary of interventions 1-26 which I have found most useful. Providing I'm not too late I would like to make some comments relating primarily to the earlier topics of discussion (Sessions 1 and 2).

[45-1] In my work as an independent land resource consultant, the main factor that has struck me as a major cause of land degradation (whatever that may be considered to be (q.v.)) is that of land tenure. In many, if not most, rural areas, the insecurity of tenure is the major factor in so-called land misuse. Farmers are, not surprisingly, unwilling to invest in soil conservation measures, water conservation structures, hedgerows and trees if that land can be taken away from them at any time. As a consultant working on river basin master plans (Rift Valley Lakes and Omo-Gibe) in Ethiopia in the early to mid 1990s, at a time when land tenure reform was being discussed, we called for (to no avail) a means whereby farmers could be given security of tenure in return for undertaking simple soil conservation measures such as planting hedgerows around their fields and homesteads.

[45-2] I agree up to a point with Nilo Alfonso (intervention 12) that in subsistence agriculture farmers simply do not have the means to implement erosion control measures or reafforestation without outside intervention. However, there are instances where land pressure has increased to such a degree that the local community has had no option but to change its land use practices by itself. Rice terraces are a prime example, as are the stone terraces in Yemen and also in Konso in south-western Ethiopia. In Konso, a semi-arid area, a man has to build a terrace before he is allowed to marry, it appears to work! Also in SW Ethiopia the Wolayta area around Sodo with a population density of around 400/km2 has much less visible erosion than the area to the north around Hosaina. However land pressure in Wolayta is huge and there are food shortages, (it is known as an area of green famine), a coping strategy is to convert from cereal crops to enset.

[45-3] In response to Ian Calder's Background Paper I would like to add the myth that 'shifting cultivators are the main initiators of erosion' in (previously) forested hilly areas. This myth pertains, not so much with land and water professionals and field workers but more worryingly, in the corridors of power and with the decision makers. An example either of the very slow rate of knowledge transfer between professionals in the field and decision makers or merely the existence of convenient scapegoats.

[45-4] In relation to this and as a practical definition of land degradation (Ian Calder, intervention 11), the Chittagong Hill Tracts in Bangladesh are characterised by a monsoon climate, steep slopes, poor soils, extensive deforestation and increasing land pressure due to in-migration which has led to soil erosion over much of the area. This is commonly attributed to shifting cultivation or jhum even though jhum accounts for only 4-6% of the total area. The area under jhum cultivation varies from year to year and is decreasing. The fallow period, historically 10-20 years, has declined to around 3 years and productivity has declined to the extent that many jhumias feel that jhum is no longer sustainable in that the area of land that can be farmed in a season is no longer capable of feeding the average family. One solution proposed is, of course, that of hedgerow intercropping, and species trials are being carried out in a number of locations.

[45-5] On this point I would readily agree with Ian Calder's Background Paper that agroforestry still has a long way to go before it is likely to be enthusiastically embraced by farmers who are asked to give at least 20% of their land over to hedgerows or tree crops with a subsequent huge increase in labour. Taking the Philippines as an example, despite long-term research and extension, farmer adoption of soil conservation technologies remains low. In high profile projects such as in Southern Mindanao, reported adoption rates are in the order of 40-60% although fewer than 30% of farmers who had started SALT (Sloping Agricultural Land Technology) in Southern Mindanao, had maintained or expanded it. Farmers needed grants to undertake SALT practices and even with grants, agroforestry farmers (SALT 3) failed to sustain contoured hedgerows, probably due to loss of productive area while waiting for trees to produce. There was a high correlation between security of tenure and SALT uptake. The most innovative farmers, those who readily took to SALT technology tended to be land owners rather than tenants.

[45-6] In practice, the most likely way to get SALT or any other conservation farming practices to be adopted and succeed, is by raising environmental awareness among farming communities and associating economic activities with viable environmental conservation measures. But because the land area is decreased (for instance by about 21% for a 0.04ha plot on 16% slope and 3-4m hedgerow interval) then the need to intensify production can also lead to an increase in the use of inorganic fertilisers and pesticides with long term environmental implications.

[45-7] Whilst it appears that although there may be net financial benefit after 3-5 years, before then, the loss in area cultivated is not compensated for by higher yields. The World Bank has expressed doubts whether the loss in croppable area from SALT can ever be compensated for by higher unit returns. There is little doubt, however, that hedgerow cropping is a useful tool in combating soil erosion per se. If governments wish to see it introduced as part of an overall strategy of reversing land degradation and combating rural poverty (the support of development to enable transfer out of a purely subsistence economy, as stated by Bo Appelgren in intervention 6), they will have to subsidise farmers for the loss of productive land and the increased labour requirements.

The contributor is Land Resources Consultant in Winchester, UK

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Good day everyone,

as the workshop is entering the second half, allow us to share some brief observations. First of all, we would like to thank you very much for the interesting interventions so far. The contributions have been very focused and have shed a lot of light on this extremely complex issue with which we are dealing. We suggest we explore some of the (yet) darker corners...

Part 1: The Landscape Perspective

[47-1] Many interventions have outlined interesting examples regarding land use impacts on water resources in different climatic and socio-economic conditions. One open issue is the scale at which land use practices have a verifiable impact on water resources availability and quality. This information is absolutely crucial when we discuss benefit-sharing instruments between upstream and downstream resource users.

[47-2] Obviously, when land use impacts do not extend beyond the plot level, it does not make sense to talk about benefit-sharing arrangements on a watershed scale. On the other hand, if there are measurable impacts of upstream land use on downstream water resources, such arrangements may lead to a better use of land and water resources in the watershed. Clearly, the relevant scale(s) will differ with regard to the type of impact. Also, environmental conditions (climatic, topographic, socio-economic...) may determine the scale in which impacts can be observed.

[47-3] A first desk study yielded the following results (see discussion paper 1, par. 52):

Legend:
x Measurable impact
- No measurable impact

[47-4] At a first glance, two conclusions may be drawn from these results:

1. There are certain impacts of land uses which extend beyond the field or plot level and can affect downstream users.

2. Generally, land-use impacts on water resources are only measurable in basins of up to a few hundred square kilometers, with the exception of some quality aspects.

[47-5] Some of your comments e.g. by Thomas Hofer (int. 5) and Patrick Moriarty (int. 26) support these assumptions with regard to floods and erosion. Also, the case studies which were submitted deal mostly with watersheds of a smaller scale. Can we, as workshop forum, verify or contest these first assumptions on the basis of our experiences with natural resource management in watersheds?

2. The Lifescape Perspective

[47-6] So far, many participants have agreed that the sharing of costs and benefits arising from natural resource management practices by upstream and downstream users in watersheds is very important. (e.g. R. Meinzen-Dick, int. 37). It was suggested that institutions or "negotiating platforms" (J. Dixon, int. 24) for different stakeholders are needed in this process. Also, secure land tenure arrangements were noted as an important prerequisite to countering land degradation on a watershed scale (Mark Hopkins, int. 45)

[47-7] Maybe it would be a helpful first step to draw up a set of criteria, or conditions, which have to be fulfilled for the successful implementation of such benefit-sharing mechanisms. The following might serve as a first draft of such criteria (modified after discussion paper 2, par. 31ff):

1. The impact of upstream land use on downstream water use is well understood.
2. The impact of land use on water resources clearly dominates over natural impacts or other anthropogenic impacts.
3. The groups of upstream and downstream stakeholders are few and well-organized.
4. The economic impact of land use on downstream stakeholders can be quantified.
5. The incentives to upstream and downstream resource users offered by the benefit-sharing instruments are high enough so that the users give preference to the instruments over alternative solutions to their problems.
6. There is political commitment to establish upstream-downstream linkages.
7. There is a strong institutional and legal framework, including land tenure structure, which allows for the implementation of benefit-sharing instruments.

[47-8] As a forum, can we endorse and validate these criteria on the basis of our concrete experiences? Which of these criteria need to be modified or amended on the basis of past experiences in watershed management? Are any of these criteria superfluous, i.e. is the implementation of benefit-sharing arrangements feasible in the absence of the condition?

[47-9] As of yet, no intervention has provided a concrete example of the application of instruments for benefit-sharing among upstream and downstream users in rural watersheds. What are the experiences of the forum? Which instruments have yielded promising results? Which problems and constrains have been encountered in the implementation process?

We’re looking forward to your reactions. Keep up the good work.

Best regards from Rome,
The Moderators

The English abstract of the intervention is followed by the full text in French.

Natural resource managers have to deal with high economical and political stakes. They must often make decisions without appropriate knowledge about complex natural phenomenons, e.g. hydric erosion. Therefore, their strategies, are periodically challenged: as in this E-workshop about forestry (=myths !) and, in other places, about policies against soil erosion in the French Alps during the 19th entury or more recently , in the Maghreb.

One question is now answered: everybody, geomorphologists and pedologists, accept that these topics have to be dealt with at a watershed scale, but their limits are different from administrative ones.. new problems!

We have to collect some more success stories as in the Philippines (Background paper No. 3), and at the end I ask two small questions about Intervention 5 and the La Réunion case study (No. 24).

Suite à votre message 59 et avec mes remerciements pour la très intéressante documentation contenue dans cet E workshop.

[60-1] Depuis bien longtemps, et avant que les connaissances acquises soient parfaites, les gestionnaires sont confrontés à des enjeux économiques et politiques auxquels ils doivent faire face en proposant des solutions fondées sur des mesures et des prévisions que l'on sait le plus souvent insuffisantes, mais dont on doit se contenter.

[60-2] La complexité de ces mesures et de ces prévisions répond à celle des phénomènes naturels mis en cause, c'est pourquoi l'érosion hydrique est un domaine de recherche très actif, dont les acquis sont périodiquement remis en cause: on en a vu un exemple dans cet Atelier électronique, dans le domaine des plantations forestières en relation avec leurs effets hydrologiques.De la même façon, on a critiqué , a posteriori , les travaux de restauration des terrains en montagne menés au 19 ème Siècle dans les Alpes françaises , puis ceux de Défense et Restauration des Sols dans le Maghreb.

[60-3] En simplifiant beaucoup, on peut avancer que deux principales catégories de chercheurs s'intéressent à ces mesures : les géomorphologues qui étudient les phénomènes géographiques sur de grandes unités et les pédologues ou agronomes pour lesquels l'érosion des sols est un objet d'études localisées autant écologiques qu'économiques; tous s'accordent à considérer que l'érosion hydrique doit être étudiée et si possible gérée au niveau du bassin versant.

[60-4] Mais ces bassins versants ont des limites différentes de celles des unités administratives... nouvelle difficultés.

[60-5] L'exemple des Philippines est instructif: on a mis au point, malgré ces difficultés et les exigences de simplicité des chercheurs, une pratique simplifiée qui a été acceptée par la population: serait-il possible de recueillir d'autres cas aussi concrets ?

[60-6] Deux questions encore :

1)Dans son intervention n° 5, Thomas Hofer propose une intéressante typologie des bassins versants liant leur dimension à l'impact humain sur les relations terre-eau. Peut on savoir à quelles études il fait allusion, et sont elles citées dans sa bibliographie?

2) Le cas concret 24 sur la Réunion n'a semble-t-il pas attiré l'attention des participants. Était-il hors sujet? ou bien présentait-il un aspect trop administratif et gestionnaire?

The contributor is Bénévole Ingénieur du GREF Retraité with the Plan Bleu/Méditerranée. He resides in France.

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For what it is worth here it is.

Management of watersheds, no matter of size, is concerned with the holistic application, use, administration, coordination and corrective actions associated with social,economic, political and environmental events. Management of resources within a watershed requires all of the science and expertise needed to effectively meet the goal of stakeholders. The hierarchy of stakeholders ( communities ) influencing how watersheds are managed includes the individual, the farm or piece of land, village, city, district or county, province, country, region, and world. These stakeholders influence organization, resource property rights, government policy, management approach, market or end use and support given to projects or programs. The stakeholders are a factor related to , either directly or indirectly, business, sale and marketing of products and approval of how land and products will be assessed or taxed to carry out or participate in a program or project. Further, there are divisions within the stakeholder hierarchy by class , caste, gender, religion , ethnicity, geographical origin, length of settlement and whether they live upstream or downstream. Who are the stakeholders is complex, but the combination of a watershed community make-up must be linked to carry out management.

The fact that management of resources in watersheds is both program and project oriented has contributed to misunderstanding of what it really is. On the one hand there are programs being simultaneously developed at national and multinational levels and on the other at the local ( micro watershed ) level. Development within a watershed is fully consistent with water (shed) management. Development includes tourism, agriculture, business growth, etc. Rising population, increasing urbanization and greater demand on all ecosystem resources are high priority reasons to insure that investment is made on the health of our watersheds. In the US alone there are 4000 plus watershed associations dedicated to pro-actively educating citizens about the value and necessity of watershed management.

While there is need to do more refining on the techniques of land degradation affecting the quality and quantity of water produced within and from a watershed we have the knowledge and tools to take care of probably 90% of land use problems in the worlds watersheds. The remaining 10% is where we need research to help refine techniques. We know how to inventory soils, geology, vegetation, climate demographics, etc. We have the tools to work with in order to produce all kinds of models to display/ understand what is or is not happening in a watershed or river basin of any size. GIS and computer programs help us develop model variations. The real issue is having people understand that after years , and probably centuries, of manipulating a watershed without understanding " the big picture ", not caring , or being a victim of historic, difficult - to -break practices it may take years to stop degradation.

It is recommended that watershed management be linked as a key activity of the newly energized mountain forum -- year of the mountain program. Mountain forum has affiliated all of the worlds mountain systems, where most of the water downstream flows from. This could help put across the idea that problems or issues facing policy makers, local resource users and managers, staff developers, researchers, etc are universal. The degree of problems may be different, but the solution is generally the same whether it is in the US, Nepal , Egypt. Russia, or Costa Rica.

The contributor is President of the Berkshire Institute at Greylock, Walpole, New Hampshire, USA

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I may have missed it in the many exchanges, but if so, I will underscore its importance: the educational or "learning value" of watersheds. Watersheds are not only a hydraulic unit; they are also a conceptual frame for understanding ecological interactions and cause-effect relationships. This is what we are doing in this email conference: We are talking about the watershed as a frame of reference for understanding the land (nature) and the people inhabiting the space defined by the watershed. But the concept is also useful for those individual actors and for changing the behavior of those actors through an appreciation for up-stream and down-stream linkages. Let me give you an example from the American presidential election. Farmers in the state of Arkansas are concerned that under new guidelines from the Enivironmental Protection Agency they may need to obtain permits in order to cut trees on their own property. Since Al Gore is closely identified with the environmental side of things, his opponent is reminding farmers that he (George W. Bush) believes in the sanctity of private property and he would never let the government interfere with what a private land holder can or cannot do on his own land.

This is where "watershed consciousness" comes into play: Famers who understand watersheds, who think in terms of the watershed, will have a different concept of "private property" and would recognize that any piece of land has some influence on, and can be affected by, what happens elsewhere in the watershed.

Just as everything within the watershed is in some way related -- and watershed consciousness is the label we give to the acknowledgement of this physical fact -- so too the ecological understanding that comes along with a better appreciation of the watershed, can influence people's behavior in their actions outside their watersheds -- a change of lifestyle that comes with change in values. Why do we care what people think, or what their values are? In the March 2000 World Water Forum, three alternative scenarios were presented for what the future of 2025 can look like. The three alternatives were based on three different sets of assumptions: (1) business as usual (a continuation of current types of development), (2) technological improvements and investments (focus on high productivity and less concern about long-term sustainability) and (3) change in lifestyles along environmentally friendly, sustainable lines.

The only acceptable future -- according to these scenarios -- in which poverty and malnourishment can be reduced and the economy can still grow -- is Scenario #3, and this scenario depends, among other things, on changing the way people conceptualize development, on their values. It's fuzzy territory that we (the development community) are ill equipped to talk about very intelligently, but our own predictions are that this is what will make the difference. We can contribute to that sustainable future by utilizing the educational value of watershed awareness.

The contributor is with the Rural Development Department, The World Bank, Washington, DC, USA

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