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Modelling a More Equitable Water Future in the Andes

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Upper-basin carnation fields
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In the CPWF Andes project Mechanisms for benefit sharing to improve productivity and reduce conflicts for water in the Andes (COMPANDES), ecosystem services is the lens through which we design mechanisms to better share the benefits of water. These mechanisms range from relatively simple payments for ecosystem services schemes, like the proposed Daule Water Fund in Ecuador, through complex negotiations between a variety of stakeholders in basins with conflicts over water use and management, such as the Coello-Combeima in Colombia. In the former, a benefit sharing mechanism (BSM) is being put into place but the Water Fund needs to know how to invest resources to improve water quality and reduce soil erosion and sedimentation in the basin. In the latter, a discussion needs to take place in which a range of stakeholders are supported in developing hydro-literacy in order to negotiate a sustainable and equitable BSM for water, avoiding current conflicts.

Ecosystem Services for Agriculture

Agriculture and hydrological ecosystem services (HES) interact closely because agriculture uses a range of HES including water quantity, quality and regulation services. Agriculture also impacts HES by: (a) consuming water through transpiration that is then no longer available to downstream users, in the process providing food; (b) affecting the quality of water through the effects of fertiliser, herbicide, pesticide, manure and soil washed away in runoff; (c) affecting water regulation (in storms and during the dry season) by changing soil structure with consequent effects on infiltration rates and runoff generation.

Upper-basin carnation fields

The interaction between agriculture and ecosystem services varies spatially with biophysical characteristics and agricultural practices and temporally with weather and climate. Upstream areas influence properties and processes downstream and the impact of an intervention depends not only on the intervention but also precisely where and when it is applied. The scale of impacts depends upon not only the distribution and scale of interventions in relation to the biophysical and agricultural context of their sites of application, but also the behaviour of areas upstream and the distribution of beneficiaries (or dis-beneficiaries) of the resulting changes in ecosystem services downstream. This is complex stuff and the only way to effectively capture this complexity is by building and applying spatial models, driven by spatial data and applied to understanding scenarios for interventions.

Models for Understanding Complex Links

One such model is the WaterWorld Policy Support System (called AguaAndes when used in the Andes). Other models are available; Bagstad et al (2013) review some 17 models focused on multiple ecosystem services. WaterWorld is a sophisticated gridded spatial model of hydrological ecosystem services that can be applied at 1-square-km or 1-hectare spatial resolution anywhere using global datasets that are provided with the model. The model is web-based and easily used and has been applied in many of the CPWF and CGIAR Research Program on Water, Land and Ecosystems basins. It provides a spatial assessment of baseline ecosystem services and allows the development of scenarios for climate change, land use change, and land and water management associated with agriculture. The impacts of these scenarios on HES and the beneficiaries of HES are calculated relative to the baseline. The system is also coupled with the Water Evaluation and Planning (WEAP) tool to allow assessment of effects on water allocation.

Coello Basin, Colombia: Hydro-Literate Negotiation of Benefit Sharing

WaterWorld and WEAP have been applied in the Coello basin of Colombia in order to develop hydro-literacy in stakeholders and compare the impacts and beneficiaries of a range of scenarios for change that might be supported by a BSM. We looked at the impact of proposed mining activities and how the benefits from this activity might be used to reduce those impacts by investing in conservation, eco-efficient agriculture and management of livestock wastes. The impact of mining is intensive but limited in area, while the impact of agriculture is extensive but less intensive. BSMs that share the benefits of water used and contaminated in mining operations can support investments in agriculture that can go a long way to improving the water, land and ecosystems in this basin. Power is power (and that usually has to do with money) but knowledge helps where there is a mechanism like Colombia’s citizen call to action (in Spanish conversatorio de acción ciudadana, CAC) that gives stakeholders a seat at the table.

Areas of reduced erosion (% of baseline) after afforestation of the areas in which afforestation most reduces erosion (data from

Daule Basin, Ecuador: What to Do, and Where?

In the Daule basin of Ecuador WaterWorld has been applied alongside the Natural Capital Project’s RIOS tool to optimise BSM-supported land use and land management investments in the catchment to reduce the impacts of continued agricultural expansion on water quality, soil erosion and sedimentation. The Daule basin supports Guayaquil—Ecuador’s second largest city with a population of around 3.75 million. The basin has seen significant deforestation for agriculture and this has impacted downstream populations. A water fund is proposed and is being designed and negotiated with stakeholders.

In a The Nature Conservancy-led and COMPANDES supported consultation with stakeholders, we defined the types of intervention that might be funded by the BSM as supporting farmers to put their land under forest (AFF), protect existing forests, investing in sanitation (SANIT) and investing in eco-agricultural techniques (ECOAG). We ran scenarios for afforestation across the entire basin and identified the change in the ecosystem services of interest with afforestation for each pixel. RIOS then allowed us to define areas in which the investment can be funded by identifying those that can be afforested with the available budget, and which will have the maximum benefit on the ecosystem services received. WaterWorld was then used to apply these investment scenarios and examine the benefit, the area that benefits and the number of people that benefit (see table). It is difficult to achieve large-scale impact with limited resources for investment but better to invest wisely on the basis of knowledge and data than to gamble on guesses.

Impact of optimal resource investments on catchment level benefits. NA means investment has no modelled impact on this objective.

La Paz/El Alto – Built vs. Green Infrastructure Alternatives

The water system for La Paz and El Alto in Bolivia is failing as the provision of water services falls well below demands, particularly in El Alto. Here, modelling was part of the process for identifying the performance of different possible management adaptations to resolve this failure. The process included social network analysis, scenario development, hydrologic and integrated water resources analysis, and use of technology for data management and visualization and decision science. The strategies identified included new storage alternatives, conservation in headwater meadows, and reductions in losses in urban and irrigation distribution systems.

A WEAP model was used to represent the region’s hydrology including glaciers and the current water system distribution and allocations. Reliability of supply within agricultural vs urban users under the full range of plausible future conditions were compared, based on policy objectives set by local planners. Using data mining and visualization techniques, we compiled a large dataset and shared the results with the focal group. Their preferred, robust and integrated alternatives identified were selected for further analysis and design towards infrastructural investment.

Making the Most of Models

Models are learning tools. They stitch together data with knowledge of process and make the data accessible and useful. Models allow users to ask questions of data and knowledge. They act as a scientist does, storing and manipulating data, combining it with coded experience and knowledge and producing an answer. They are usually more consistent than scientists and sometimes cheaper and more accessible, but they do reflect the partial nature of scientific knowledge, the paucity of data that exists for much of the developing world and the opinions and biases of their developers.

There are few rules of thumb in agricultural research. Most interventions will have completely different effects when applied in different settings. Spatial models allow the combination of general knowledge of processes with specific knowledge (data) on place, which means they can be used to better understand what will work where and move away from an one size fits all mentality. This is important if sustainable intensification supporting poor farmers and the environment is to be realised at impact-relevant scales. Models should be used with caution, but they should be used.

Mark Mulligan is Reader in Geography at King’s College London and senior fellow of UNEP-WCMC. He led the CPWF Basin Focal Project for the Andes and the CPWF Phase II COMPANDES Project as well as cross-basin analyses of Water Availability and Climate Change. COMPANDES is funded by the CPWF and brings together KCL, SEI, UNAL and WWF-Colombia. It is led by Mark Mulligan and coordinated by Jorge Rubiano

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