scholarly journals Basin-scale impacts of hydropower development on the Mompós Depression wetlands, Colombia

2018 ◽  
Vol 22 (5) ◽  
pp. 2839-2865 ◽  
Author(s):  
Héctor Angarita ◽  
Albertus J. Wickel ◽  
Jack Sieber ◽  
John Chavarro ◽  
Javier A. Maldonado-Ocampo ◽  
...  
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Integrated Approach ◽  
Planning System ◽  
Hydropower Development ◽  
Ecological Processes ◽  
Development Scenarios ◽  
Basin Scale ◽  
Depression Wetlands ◽  
Order Of Magnitude

Abstract. A number of large hydropower dams are currently under development or in an advanced stage of planning in the Magdalena River basin, Colombia, spelling uncertainty for the Mompós Depression wetlands, one of the largest wetland systems in South America at 3400 km2. Annual large-scale inundation of floodplains and their associated wetlands regulates water, nutrient, and sediment cycles, which in turn sustain a wealth of ecological processes and ecosystem services, including critical food supplies. In this study, we implemented an integrated approach focused on key attributes of ecologically functional floodplains: (1) hydrologic connectivity between the river and the floodplain, and between upstream and downstream sections; (2) hydrologic variability patterns and their links to local and regional processes; and (3) the spatial scale required to sustain floodplain-associated processes and benefits, like migratory fish biodiversity. The implemented framework provides an explicit quantification of the nonlinear or direct response relationship of those considerations with hydropower development. The proposed framework was used to develop a comparative analysis of the potential effects of the hydropower expansion necessary to meet projected 2050 electricity requirements. As part of this study, we developed an enhancement of the Water Evaluation and Planning system (WEAP) that allows resolution of the floodplains water balance at a medium scale (∼ 1000 to 10 000 km2) and evaluation of the potential impacts of upstream water management practices. In the case of the Mompós Depression wetlands, our results indicate that the potential additional impacts of new hydropower infrastructure with respect to baseline conditions can range up to one order of magnitude between scenarios that are comparable in terms of energy capacity. Fragmentation of connectivity corridors between lowland floodplains and upstream spawning habitats and reduction of sediment loads show the greatest impacts, with potential reductions of up to 97.6 and 80 %, respectively, from pre-dam conditions. In some development scenarios, the amount of water regulated and withheld by upstream infrastructure is of similar magnitude to existing fluxes involved in the episodic inundation of the floodplain during dry years and, thus, can also induce substantial changes in floodplain seasonal dynamics of average-to-dry years in some areas of the Mompós Depression.

scholarly journals Large-scale impacts of hydropower development on the Mompós Depression wetlands, Colombia

2017 ◽  
Author(s):  
Héctor Angarita ◽  
Albertus J. Wickel ◽  
Jack Sieber ◽  
John Chavarro ◽  
Javier A. Maldonado-Ocampo ◽  
...  
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Planning System ◽  
Ecological Processes ◽  
Development Scenarios ◽  
Sediment Loads ◽  
Decadal Scale ◽  
Depression Wetlands ◽  
Order Of Magnitude ◽  
The Impact

Abstract. A number of large hydropower dams are currently under development or in an advanced stage of planning in the Magdalena River basin, Colombia, spelling uncertainty for the Mompós Depression wetlands, one of the largest wetland systems in South America. Annual large-scale inundation of floodplains and associated wetlands regulates water-, nutrient-, and sediment cycles, which in turn sustain a wealth of ecological processes and ecosystem services, including critical food supplies. In this study, we present a comparative analysis of the potential effects of hydropower expansion to meet projected electricity requirements by 2050, in terms of 1) basin-level implications of cumulative changes in streamflow regime, sediment trapping, and loss of river connectivity, and 2) the impact of upstream regulation on the hydrologic dynamics of the Mompós Depression wetlands at a monthly to decadal scale. To this end, we developed an enhancement of the Water Evaluation and Planning system (WEAP) that allows resolution of the Mompós Depression floodplains water balance at a medium scale (~1000 to 10 000 km2) and evaluation of the potential impacts of upstream water management practices. Our results indicate that potential additional impacts of new hydropower infrastructure with respect to baseline conditions can range up to one order of magnitude between scenarios that are comparable in terms of energy capacity. Fragmentation of connectivity corridors between lowland floodplains and upstream spawning habitats and reduction of sediment loads show the greatest impacts, with potential reductions of up to 97.6 and 80 %, respectively, from pre-dam conditions. In some development scenarios, the amount of water regulated and withheld by upstream infrastructure is of similar magnitude to existing fluxes involved in the episodic inundation of the floodplain during dry periods and, thus, can also induce substantial changes in floodplain seasonal dynamics of average-to-dry years in some areas of the Mompós Depression.

scholarly journals Medium Plant Cover has the Highest Heterogeneity of Fine-Scale Spatial Vegetation Patterns in Humid grasslands

2021 ◽  
Author(s):  
Qin Yang ◽  
Hua Cheng ◽  
Hongmei Pu ◽  
Xuechun Zhao ◽  
Rui Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Patch Size ◽  
Management Practices ◽  
Plant Cover ◽  
Rapid Expansion ◽  
Edge Density ◽  
Vegetation Patterns ◽  
Fine Scale ◽  
Ecological Processes ◽  
Patch Density

Abstract Context Fine-scale spatial vegetation patterns are ubiquitous and can have profound impacts on large scale ecological processes including surface runoff, soil erosion, and livestock forage efficiency. However, we have limited knowledge of the fine-scale spatial vegetation patterns in humid grasslands.Objectives The objectives were to characterize the spatial vegetation patterns at centimeter scale in humid grasslands, quantify the vegetation patterns variation under different image pixel sizes and plant covers, and explore the potential ecological implications of the spatial vegetation patterns.Methods Seventy plots with plant covers ranging from 30.8–99.3% were selected from seven humid grasslands in southwest China and their spatial vegetation patterns quantified at image pixel sizes of 0.04, 0.25, 1, and 4 cm.Results With increasing pixel size, plant patch density and total edge density decreased, plant patch size increased, and the plant patch shape became more regular. At a plant cover level below 50%, increasing plant cover will result in increasing patch density and patch size, leading to greater spatial heterogeneity. At plant cover levels above 50%, increasing plant cover will cause the rapid expansion of patch size, along with a lower patch density, forming a more homogeneous landscape dominated by plant patches. The small stems, branches, and leaves of grasses fragmented non-plant patches into smaller patches with increasing plant cover; this fragmentation resembles road-induced landscape fragmentation processes.Conclusions Medium plant cover has the highest heterogeneity of spatial vegetation pattern at the fine scale, which may have significant implications on ecological processes and related management practices.

scholarly journals The phytosociology of the Vermaaks, Marnewicks and Buffelsklip valleys of the Kammanassie Nature Reserve, Western Cape

Koedoe ◽  
2005 ◽  
Vol 48 (1) ◽  
Author(s):  
G. Cleaver ◽  
L.R. Brown ◽  
G.J. Bredenkamp
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Nature Reserve ◽  
Western Cape ◽  
Groundwater Abstraction ◽  
Ecological Processes ◽  
Vegetation Surveys ◽  
Baseline Information

Long-term conservation ecosystems require a broader understanding of the ecological processes involved. Because ecosystems react differently to different management practices, it is important that a description and classification of the vegetation of an area are completed. A vegetation survey of the valley areas of the Kammanassie Nature Reserve was undertaken as part of a larger research project to assess the environmental impacts of large-scale groundwater abstraction from Table Mountain Group aquifers on ecosystems in the reserve. From a TWFNSPAN classification, refined by Braun-Blanquet procedures, 21 plant communities, which can be grouped into 13 major groups, were identified. A classification and description of these communities, as well as a vegetation map of the different areas are presented. Associated gradients in habitat w ere identified by using an ordination algorithm (DECORANA). The diagnostic species as well as the prominent and less conspicuous species of the tree, shrub, forb and grass strata are outlined. The study also resulted in a total number of 481 species being identified and the discovery of a new Erica species. These vegetation surveys and descriptions provide baseline information for management purposes and that allows monitoring as well as similar surveys to be conducted in future.

An Integrated Approach for Maximising Local and Scientific Knowledge for Land Management Decision-Making in the New Zealand High Country.

1996 ◽  
Vol 18 (1) ◽  
pp. 23 ◽  
Author(s):  
OJH Bosch ◽  
WJ Allen ◽  
JM Williams ◽  
AH Ensor
Keyword(s):  
Decision Making ◽  
New Zealand ◽  
Land Management ◽  
Large Scale ◽  
Management Practices ◽  
Integrated Approach ◽  
Integrated System ◽  
Management Decision ◽  
Monitoring Tools ◽  
Management Decision Making

This paper describes the development of a process to facilitate the identification and introduction of sustainable land management practices in the high country of New Zealand. The process was designed to gather and structure community knowledge (both local and scientific) into a single, accessible decision support system (DSS). The development and provision of appropriate, and user-friendly monitoring tools is supported. An outline is given of how this integrated system can be used to integrate monitoring with adaptive management. Special reference is made to how this process is used as a large-scale ecological 'experiment', to enhance continually the knowledge base available for land use decision-making in the South Island high country of New Zealand.

scholarly journals The Impact of Soil-Improving Cropping Practices on Erosion Rates: A Stakeholder-Oriented Field Experiment Assessment

Land ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 964
Author(s):  
Ioannis K. Tsanis ◽  
Konstantinos D. Seiradakis ◽  
Sofia Sarchani ◽  
Ioanna S. Panagea ◽  
Dimitrios D. Alexakis ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Water Conservation ◽  
Large Scale ◽  
Management Practices ◽  
Order Of Magnitude ◽  
Erosion Mitigation ◽  
Imminent Threat ◽  
Fruit Orchards ◽  
Eu Project ◽  
The Impact

The risk of erosion is particularly high in Mediterranean areas, especially in areas that are subject to a not so effective agricultural management–or with some omissions–, land abandonment or wildfires. Soils on Crete are under imminent threat of desertification, characterized by loss of vegetation, water erosion, and subsequently, loss of soil. Several large-scale studies have estimated average soil erosion on the island between 6 and 8 Mg/ha/year, but more localized investigations assess soil losses one order of magnitude higher. An experiment initiated in 2017, under the framework of the SoilCare H2020 EU project, aimed to evaluate the effect of different management practices on the soil erosion. The experiment was set up in control versus treatment experimental design including different sets of treatments, targeting the most important cultivations on Crete (olive orchards, vineyards, fruit orchards). The minimum-to-no tillage practice was adopted as an erosion mitigation practice for the olive orchard study site, while for the vineyard site, the cover crop practice was used. For the fruit orchard field, the crop-type change procedure (orange to avocado) was used. The experiment demonstrated that soil-improving cropping techniques have an important impact on soil erosion, and as a result, on soil water conservation that is of primary importance, especially for the Mediterranean dry regions. The demonstration of the findings is of practical use to most stakeholders, especially those that live and work with the local land.

Sustainable Production of Honeydew and Muskmelon in Western Mexico

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 495d-495
Author(s):  
J. Farias-Larios ◽  
A. Michel-Rosales
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Glomus Intraradices ◽  
Cultural Practices ◽  
Bare Soil ◽  
Western Mexico ◽  
First Results ◽  
Legume Cover Crop ◽  
Banana Leaves ◽  
Research Show

In Western Mexico, melon production depends on high-input systems to maximize yield and product quality. Tillage, plasticulture, fumigation with methyl bromide, and fertigation, are the principal management practices in these systems. However, at present several problems has been found: pests as sweetpotato whitefly (Bemisia tabaci Gennadius), aphids (Myzus and Aphis), leafminer (Liryomiza sativae); diseases as Fusarium, Verticilium, and Pseudoperenospora, and weeds demand high pesticide utilization and labor. There is a growing demand for alternative cultural practices, with an emphasis on reducing off-farm input labor and chemicals. Our research is based on use of organic mulches, such as: rice straw, mature maize leaves, banana leaves, sugarcane bagasse, coconut leaves, and living mulches with annual legume cover crop in melons with crop rotation, such as: Canavalia, Stilozobium, Crotalaria, and Clitoria species. Also, inoculations with mycorrhizal arbuscular fungi for honeydew and cantaloupe melon seedlings production are been assayed in greenhouse conditions for a transplant system. The use of life barriers with sorghum, marigold, and other aromatic native plants in conjunction with a colored yellow systems traps for monitoring pests is being studied as well. While that the pest control is based in commercial formulations of Beauveria bassiana for biological control. The first results of this research show that the Glomus intraradices, G. fasciculatum, G. etunicatum, and G. mosseae reached 38.5%, 33.5%, 27.0%, and 31.0% of root infection levels, respectively. Honeydew melons production with rice and corn straw mulches shows an beneficial effect with 113.30 and 111.20 kg/plot of 10 m2 compared with bare soil with 100.20 kg. The proposed system likely also lowers production cost and is applicable to small- and large-scale melon production.

Large-Scale Application of Biofiltration Swale Runoff Management Practices

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
William C. Lucas
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Peak Flow ◽  
Low Impact Development ◽  
Urban Runoff ◽  
Management Model ◽  
Check Dams ◽  
Runoff Reduction ◽  
Impervious Area ◽  
Hydrologic Responses

Retaining rainfall where it lands is a fundamental benefit of Low Impact Development (LID). The Delaware Urban Runoff Management Model (DURMM) was developed to address the benefits of LID design. DURMM explicitly addresses the benefits of impervious area disconnection as well as swale flow routing that responds to flow retardance changes. Biofiltration swales are an effective LID BMP for treating urban runoff. By adding check dams, the detention storage provided can also reduce peak rates. This presentation explores how the DURMM runoff reduction approach can be integrated with detention routing procedures to project runoff volume and peak flow reductions provided by BMP facilities. This approach has been applied to a 1,200 unit project on 360 hectares located in Delaware, USA. Over 5 km of biofiltration swales have been designed, many of which have stone check dams placed every 30 to 35 meters to provide detention storage. The engineering involved in the design of such facilities uses hydrologic modeling based upon TR-20 routines, as adapted by the DURMM model. The hydraulic approach includes routing of flows through the check dams. This presentation summarizes the hydrological network, presents the hydrologic responses, along with selected hydrographs to demonstrate the potential of design approach.

DESIGN AND IMPLEMENTATION OF THE OCEANOGRAPHIC MODELING AND OBSERVATION NETWORK (REMO) FOR PHYSICAL OCEANOGRAPHY STUDIES AND OCEAN FORECASTING

2014 ◽  
Vol 31 (2) ◽  
Author(s):  
Jose Antonio Moreira Lima
Keyword(s):  
Atlantic Ocean ◽  
Large Scale ◽  
North Pacific Ocean ◽  
Integrated Approach ◽  
Sea Surface ◽  
Global Ocean ◽  
Height Anomaly ◽  
The North ◽  
Observation Network ◽  
Ocean Forecasting

This paper is concerned with the planning, implementation and some results of the Oceanographic Modeling and Observation Network, named REMO, for Brazilian regional waters. Ocean forecasting has been an important scientific issue over the last decade due to studies related to climate change as well as applications related to short-range oceanic forecasts. The South Atlantic Ocean has a deficit of oceanographic measurements when compared to other ocean basins such as the North Atlantic Ocean and the North Pacific Ocean. It is a challenge to design an ocean forecasting system for a region with poor observational coverage of in-situ data. Fortunately, most ocean forecasting systems heavily rely on the assimilation of surface fields such as sea surface height anomaly (SSHA) or sea surface temperature (SST), acquired by environmental satellites, that can accurately provide information that constrain major surface current systems and their mesoscale activity. An integrated approach is proposed here in which the large scale circulation in the Atlantic Ocean is modeled in a first step, and gradually nested into higher resolution regional models that are able to resolve important processes such as the Brazil Current and associated mesoscale variability, continental shelf waves, local and remote wind forcing, and others. This article presents the overall strategy to develop the models using a network of Brazilian institutions and their related expertise along with international collaboration. This work has some similarity with goals of the international project Global Ocean Data Assimilation Experiment OceanView (GODAE OceanView).

scholarly journals Precision Agriculture for Resource Use Efficiency in Smallholder Farming Systems in Sub-Saharan Africa: A Systematic Review

2021 ◽  
Vol 13 (3) ◽  
pp. 1158
Author(s):  
Cecilia M. Onyango ◽  
Justine M. Nyaga ◽  
Johanna Wetterlind ◽  
Mats Söderström ◽  
Kristin Piikki
Keyword(s):  
Resource Use ◽  
Precision Agriculture ◽  
Large Scale ◽  
English Language ◽  
Management Practices ◽  
Smallholder Farmers ◽  
Management Strategies ◽  
Sub Saharan Africa ◽  
Smallholder Farming ◽  
Sub Saharan

Opportunities exist for adoption of precision agriculture technologies in all parts of the world. The form of precision agriculture may vary from region to region depending on technologies available, knowledge levels and mindsets. The current review examined research articles in the English language on precision agriculture practices for increased productivity among smallholder farmers in Sub-Saharan Africa. A total of 7715 articles were retrieved and after screening 128 were reviewed. The results indicate that a number of precision agriculture technologies have been tested under SSA conditions and show promising results. The most promising precision agriculture technologies identified were the use of soil and plant sensors for nutrient and water management, as well as use of satellite imagery, GIS and crop-soil simulation models for site-specific management. These technologies have been shown to be crucial in attainment of appropriate management strategies in terms of efficiency and effectiveness of resource use in SSA. These technologies are important in supporting sustainable agricultural development. Most of these technologies are, however, at the experimental stage, with only South Africa having applied them mainly in large-scale commercial farms. It is concluded that increased precision in input and management practices among SSA smallholder farmers can significantly improve productivity even without extra use of inputs.

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