Since 2010, Chile has been affected by a long-term drought, often referred to as the Mega-Drought. To adapt to future drought events, we need reliable hydro-climatic information based on robust observations and models. However, reliable hydro-climatic data needed for hydrological modelling of remote Andean catchments are rarely available. Our objective was therefore to identify the most suitable combination of different rainfall estimates with two rainfall-runoff models of varying complexity to reliably simulate low flows related to drought.We forced the widely used SWAT and HBV-light models with four satellite-based rainfall estimates (SREs) (CHIRPSv2, MSWEPv1.2, MSWEPv2.0, TMPA 3B42v7) and inverse distance weighted (IDW) precipitation observations for the main headwater catchment of the Imperial River basin (Araucania, 38°N). Sobol global sensitivity analysis and calibration were carried out using the hydroPSO R package, using two objective functions focused on the performance of low flows (logNSE and low flows KGE).Despite the differing amount and temporal distribution of water, for all four SREs, the Sobol sensitivity analysis resulted in robust identification of key model parameters for all SWAT optimisation runs, with most sensitivity for parameters related to deep groundwater recharge, lateral flow travel time and the SCS runoff curve number. For the HBV-light model, only parameters related to snow-melt and deep groundwater recharge were robustly identified for the wetter SRE products. For both models and the two objective functions, the best efficiencies were obtained with the wetter SREs (MSWEP v1.2 and CHIRPSv2) as well as with IDW.We found that SREs combined with rainfall-runoff modelling provide a valuable instrument to simulate daily discharges for the Upper Imperial River Basin. The resulting models are hence suitable to project low flows and water availability; information that is requested by local decision makers needed to design irrigation systems for the agricultural downstream area and the secure water supply of settlements in the context of future droughts.
The seasonally-dry tropics of northern Costa Rica are characterized by recurrent drought events with negative socio-economic impacts on a vulnerable population. Scarce hydroclimatic observational data constraints reasonable water management and often results in water scarcity issues.This study analyses hydrological drought situations using freely available Global Precipitation Products (GPP) and a Regional Climate Model (RCM) that drive a relatively simple, semi-distributed rainfall-runoff model (HBV-Light). Firstly, the GPP and observed rainfall were used to calibrate the model simulating streamflow dynamics. Secondly, drought detection and estimates of drought duration, intensity and severity were determined with a daily variable threshold approach. Thirdly, we developed future hydrological drought scenarios based on a RCM. Generally, the GPP CHIRPS (Climate Hazards Group InfraRed Precipitation with Station Data) resulted in the best streamflow simulations (KGE > 0.6) compared with the model driven by observed rainfall (KGE > 0.7). CHIRPS also correctly identified the observed streamflow drought periods of 1994, 1997-1998 and 2001-2002.Average observed streamflow drought severity was 27.9 mm compared to the CHIRPS-derived severity of 20.6 mm (error estimate of ±7.3 mm). The model in combination with global data can be successfully used to identify drought periods and their duration, but model uncertainty currently prevents from forecasting streamflow deficit with volume errors below 50%. The future hydrological drought scenario showed more severe drought periods between 2039-2041 and 2042-2043.This study responds to the need for drought assessments in the seasonally-dry tropics with scarce observations as a tool for adaptation to climate change and water resource management.
Background: Despite the key role topsoil plays in reclamation, there are situations where topsoil is in deficit or unavailable, especially at degraded and abandoned mine sites in Ghana. The sites pose serious ecological and safety risks, underscoring the urgent need to finding alternative substrate for restoration. This study investigated the feasibility of using amended-subsoil as topsoil substitute for reclamation. The hypothesis was that amendment of stockpiled-subsoil with poultry manure positively influences tree growth and ground vegetation cover (GVC), which promote better soil stabilization at degraded mine sites. A graded waste-rock dump was covered with a 70 cm layer of the stockpiled subsoil at Newmont Ghana Gold Limited. Two experimental plots (24 × 15 m) were established with the treatments poultry manure (PLM 23 t ha-1) and control (no PLM), followed by seeding of Cowpea (Vigna unguiculata) and planting of potted-seedlings of five forest tree species. The Laser-point-quadrat method was used to estimate GVC, whereas erosion was visually observed. Diameter and height data of planted trees and surviving numbers were collected.Results: There was significant increase in tree growth and in GVC for the poultry manure treatment compared to the control. The manure provided sufficient nitrogen to overcome nitrogen deficiency and facilitated quicker and stronger vegetation growth that yielded superior soil stabilization.Conclusions: The findings demonstrate the potential of manure application in promoting successful restoration of the many degraded and abandoned mine sites in Ghana to productive uses.
Photovoltaics (PV) are a rapidly growing technology as global energy sectors shift towards “greener” solutions. Despite the clean energy benefits of solar power, photovoltaic panels and their structural support systems (e.g., cement) often contain several potentially toxic elements used in their construction. Determining whether these elements have the potential to leach into surrounding environments should be a research priority, as panels are already being implemented on a large scale. In this study, we analyzed soil taken from beneath photovoltaic modules to determine if they are being enriched by metals (lead, cadmium, lithium, strontium, nickel, barium, zinc, and copper) and metalloids (selenium) present in panel systems. The soil samples were collected from directly beneath c-Si photovoltaic modules and adjacent fields. Samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). Selenium, strontium, lithium, nickel, and barium levels measured in soil samples increased significantly in samples closer to PV systems. There were no significant differences in lead or cadmium levels near vs. far from the PV systems. Despite concentration differences for some elements near vs. far from the panel systems, no elements were, on average, present in concentrations that would pose a risk to nearby ecosystems. PV systems thus remain a cleaner alternative to traditional energy sources, such as coal, especially during the operation of these energy production systems.
Globally, clean cookstoves represent the best substitute for open fire biomass stoves in order to reduce greenhouse gas emissions from fuelwood. Prospects to transfer this technology to Botswana are being explored. Our research objectives were to transfer the clean Institutional Cookstove (IC) technology to Okavango Research Institute (ORI), quantify the amount of mopane (Colophospermum mopane) fuelwood it consumes in comparison to the traditional biomass energy system, and analyze its potential to be used as a substitute for the open fire cooking method. The clean IC technology transfer to ORI was successfully completed before testing its energy efficiency and financial viability. It consumed approximately two-thirds less fuelwood than the traditional three stone stove. This presents an opportunity for a reduction in greenhouse gas emissions from fuelwood consumption in Botswana. This is a critical consideration in an environment where there is limited readily available fuelwood. The use of clean cookstoves allows enhanced carbon sequestration by live mopane woodland resources. A financial viability analysis of implementing the clean IC in primary schools showed that it has the potential to save money spent on fuelwood. Our case study provides essential pertinent results on the energy efficiency of the developed prototype, which forms a basis for further research on the use of clean cookstoves for mitigating greenhouse gas emissions from fuelwood consumption in Botswana and the entire Cubango-Okavango River Basin. A comprehensive analysis of cultural barriers to adoption of the technology will be carried out through piloting the construction of the clean cookstove.
This paper presents the modeling and simulation of the characteristics and electrical performance of photovoltaic (PV) solar modules. Genetic coding is applied to obtain the optimized values of parameters within the constraint limit using the software MATLAB. A single diode model is proposed, considering the series and shunt resistances, to study the impact of solar irradiance and temperature on the power-voltage (P-V) and current-voltage (I-V) characteristics and predict the output of solar PV modules. The validation of the model under the standard test conditions (STC) and different values of temperature and insolation is performed, as well as an evaluation using experimentally obtained data from outdoor operating PV modules. The obtained results are also subjected to comply with the manufacturer’s data to ensure that the proposed model does not violate the prescribed tolerance range. The range of variation in current and voltage lies in the domain of 8.21 – 8.5 A and 22 – 23 V, respectively; while the predicted solutions for current and voltage vary from 8.28 – 8.68 A and 23.79 – 24.44 V, respectively. The measured experimental power of the PV module estimated to be 148 – 152 W is predicted from the mathematical model and the obtained values of simulated solution are in the domain of 149 – 157 W. The proposed scheme was found to be very effective at determining the influence of input factors on the modules, which is difficult to determine through experimental means.
Dolines are karst depressions whose environmental and climatic characteristics in tropical regions are not well known. By measuring and analyzing different components of the microclimate in two dolines located in Tamasopo, Mexico, we aim to contribute to the understanding of the climatic conditions in these formations. The variables analyzed include temperature, solar radiation, soil and air humidity, as well as their relationship to physical and chemical characteristics of the soil such as pH, conductivity, texture, and the content of organic matter, carbon, nitrogen, phosphorus, calcium, potassium, sodium and magnesium. Measurements and soil samples were taken in three strata: bottom, slope and exterior. The results show a gradient in the climatic variables along the three strata, as well as higher concentrations of all elements, except phosphorus, in soil from the dolines, with respect to the exterior. Furthermore, statistical analysis shows a high correlation between the environmental conditions and edaphic properties. The micro climatic factors of the dolines generate a different environment, rich in humidity and with temperatures commonly lower than those present in tropical regions. These conditions cause abrupt changes in the physical and chemical composition of the soil, which present high concentrations of nutrients.
Tanzania has experienced many natural resource use conflicts in many parts of the country, including the Kilosa and Mvomero districts, ranging from family disputes through to all-out social unrest. Despite some efforts to curb rampant natural resource use conflicts, there is overwhelming evidence of the existence and upsurge of such conflicts, leading to various consequences, including death of people involved, destruction of property and the creation of a sense of insecurity. This study aims to characterize and map the causes, intensity and effects of natural resource use conflicts in the districts of Kilosa and Mvomero, Tanzania. Key Informant Interviews were used to gather valuable evidence to characterize the natural resource use conflicts in Kilosa and Mvomero, which also aided in constructing natural resource-use conflict typology. Quantum GIS software was used for spatial mapping of the conflicts. The study confirmed that land, water, crops, pasture and minerals are the main natural resources behind the conflicts, and therefore these resources have to be treated as crucial dimensions of conflict prevention in Kilosa and Mvomero. Generally, there is complexity in the conflict situations and overlapping of causes and conflict types on the one hand, and overlapping of conflict types and resources which are contested for on the other.
In Ethiopia, wood was the main construction material for rural houses. In 2013, about 79% of the rural houses of Ethiopia were fully made of wood. Although carbon storage of wood is well known for climate change mitigation, there is lack of information on carbon stock of wooden houses in Ethiopia. Thus, a study was conducted to analyze the carbon stock of dominant land uses that surround rural wooden houses in three agro-ecologies and representative three peasant associations (PA) or Kebeles in Southern Ethiopia. Field measurement and household survey were made by selecting sixty-four houses made of wood, grass or corrugated iron sheet. Transects were laid starting from the wooden houses to lay out plots to collect samples of wood, grass, soot inside houses, soil and trees for carbon determination. The service age of wooden houses was estimated in triangulated interview as 5-150 years. The total carbon stock of newly constructed rural grass covered wooden house was 28.35- 49.26 kg C m-2, which was greater than the other surrounding land uses. The grazing land total carbon stock was 50.5-86.8% and the scattered trees carbon was 9.5-59.7% of the total carbon stock of the respective PA grass covered wooden house. Since soil is the common below ground carbon stock, the total carbon of a land use is mostly affected by the above ground carbon stock. Grass covered houses contained greater above ground carbon stock but grazinglands contained greater below ground carbon stock. Soot accumulation of 0.4-1.3 g m-2 inside the houses’ roof indicated the presence of indoor pollution. The total carbon stock increased with increasing altitude and geoclimatic variables were significantly correlated with carbon stock of the land uses (p<0.05; r = ±0.999). Therefore, wooden houses need to be considered in climate change mitigations. The shift of carbon stock from natural environment to wooden houses in human dominated landscapes was indicator of a lack of forests, and then efforts should be strengthened to increase forest cover.
Climate change is considered one of the most serious threats to sustainable development in the world. As a sector, agriculture is very dependent on climatic conditions, which makes it extremely vulnerable to the impacts of climate change and variability. The semi-arid areas of the world are especially more vulnerable to the impacts of climate change and variability. The purpose of this study was to determine how farmers adapt to changing climate in Narok East, and determine the factors that influence their choice of response strategies. Data was collected from 223 household heads using a semi-structured questionnaire. Data was analysed using descriptive statistics to determine how farmers adapt to climate change and variability while Principal Component Analysis and a multivariate probit model were used to assess the factors that influence the choice of response strategies. The results showed that early planting, increased use of manure, use of terraces, increased use of inorganic fertilisers, and planting short season crops were the most widely used strategies while the least used were planting agroforestry trees, crop diversification and irrigation. Results of the multivariate probit model showed that the age of the household head, total household size, level of education of the household head, noticing changes in mean annual rainfall and onset of rains, receiving weather information, and the land tenure system were all significant factors that influence the choice of the response strategy. This study, therefore, recommends boosting more education and climate change awareness for the farmers of Narok East Sub-county.
Collaborative resource management has been touted as one of the ways conservation of wildlife resources can be improved, especially in off-protected areas. Three indicators were used to test whether collaboration between the Wildlife Division of the Forestry Commission of Ghana and local communities has any impact on farmers’ perspectives on crop raiding. The indicators were: (1) methods used by farmers to reduce raiding, (2) institutions to which farmers report raids, and (3) the kind of assistance needed to reduce raiding. The findings suggest there were no differences between the collaborative indicators and the two chosen study locations. However, on the question of institutions where raiding incidences were reported and location, the difference was significant (X2=14.523; DoF= 5; P=0.01261). In addition, there was a statistically significant relation between location and participants’ responses to species that raided their crops (X2=16.988; DoF=4; p= 1.943e-3). Participants from the two locations did not show differences in their responses to preventive methods. Male respondents mentioned the use of traps as their major preventive method, although this is against wildlife hunting regulations in Ghana. Educating and supporting farmers with appropriate preventive methods that reduce their losses to wildlife crop raiding is recommended to improve conservation.
In southeastern Bangladesh, where water quality in the upper aquifers is a serious constraint, future development will likely be confined to deep fresh groundwater. Owing to the importance and pervasive use of deep groundwater, the sustainability of water use has received extensive attention. However, excessive extraction from deep aquifers may pose a threat to the storage as well as the quality of water due to the high susceptibility to salinization and arsenic contamination from upper aquifers. Hence, determining the extension of aquifer units and the characterizing aquifer sediments are very important to ensure sustainable development and management of limited fresh groundwater resources. The study area extends over six districts of the southeastern coastal region of Bangladesh. In order to assess and monitor deep fresh groundwater potential in the study area, aquifer pumping tests were performed at six locations with up to 72 h of constant-discharge prior to recovery. Different methods were used to analyze the drawdown and recovery data considering aquifers as confined or leaky-confined. Based on transmissivity values it was found that the studied deep aquifers have moderate to high potential for potable water supply. However, this deep fresh groundwater may not be safe for a longer period where upper aquifer units contain saline groundwater and where there is no significant aquitard encountered above or below the deep aquifer. Irrigation extraction of the deep groundwater is not recommended.
This paper explores the approach used by fisheries-related stakeholders to break the complex relationship between fishermen and middlemen in the fishing village of Pangandaran, West Java, Indonesia. This location was selected because the fisheries trade there has been institutionalized by the presence of rural enterprise. This is unusual, especially in traditional small-scale fisheries where trade is governed by middlemen. The information was obtained by interviewing key stakeholders from various parties and combining this with relevant secondary data. The main argument is that formalizing the fisheries market is not as simple as implementing technical regulations. There are non-technical factors that affect the entire process. The findings indicate that trust is the important variable that catalyzes the process and binds stakeholders in certain trading mechanisms. Furthermore, this situation is very helpful to divert the fishermen from patron-client relationships that are often unfavorable in the long term.
Energy is essential for sustainable development and for improving the socio-economic welfare of a community. Sub-Saharan Africa suffers from severe rural energy poverty and minimal access to modern energy services. Adoption of renewable energy technologies is often viewed as a way to alleviate rural energy poverty, but uptake is slow. Socio-economic factors, mainly household income, electricity access, fuels used for cooking, and land tenure, influence adoption of renewable energy technologies. This paper assesses the contribution of small hydropower and biogas technologies in alleviating rural energy poverty in Kirinyaga County, Kenya, where the majority of the population relies on traditional sources of energy. A case study research design was used, with a sample size of 178. Data was collected using a questionnaire survey, the review of project documents, and interviews. Five indicators were used to assess energy poverty. The results indicate medium to low energy poverty and energy stacking; with reliance on traditional sources of energy. Socio-economic factors influence adoption of SHP and biogas. Therefore, adoption of renewable energy technologies does not alleviate rural energy poverty because SHP and biogas are used to supplement rather than replace the use of traditional fuels.
Infiltration into soils of pesticides used during agricultural production has led to the contamination of aquatic ecosystems due to their long persistence in the environment. Some pesticides (e.g. Chlorpyrifos) are inhibitors of cholinesterase enzyme activity and their presence in water samples can be indirectly detected by a decrease in enzymatic activity. Biosensors based on cholinesterase enzymes are an alternative for the sensitive detection of important contaminants in the environmental sector. Acetylcholinesterase enzyme (AChE) catalyzes the hydrolysis of acetylthiocholine (ATCh) to produce thiocholine (TCh). This feature can be employed to measure the decrease in AChE activity. The inhibitory characteristics of the AChE-Chlorpyrifos system have been studied through cyclic voltammetry, by evaluation of the oxidation of the thiol group, which corresponds to TCh production on platinum electrodes in the presence of an inhibitor. In the present study, enzymatic curves were obtained at different concentrations of substrate and inhibitor, which were then used to determine the enzymatic kinetics corresponding to a mixed inhibition type, with an inhibition constant (Ki) of (18.26 ± 0.01) μM. TCh electrochemical detection appears to be a promising option for the development of biosensors to identify and quantify pesticides present in the ecosystem.
This study compares the only residential Passivhaus in Mexico (located in Mexico City) to a conventional building-practice home in terms of indoor environmental quality during summer, specifically indoor air quality (IAQ) and the occupants’ perceptions towards it. Temperature, relative humidity, carbon dioxide, and PM2.5 were monitored during May, June and July 2016 in the living room, bedroom and kitchen of each home. Simultaneous outdoor air measurements were collected from the local pollution monitoring network. Online surveys were used to obtain data on building-related illnesses; while occupant perception of IAQ and thermal comfort and occupant diaries helped to provide insights into occupant behavior. Results from this case study suggest that Passivhaus design strategies could help to protect building occupants from outdoor air pollution, based on the lower concentrations of PM2.5 that were found in the Passivhaus apartment compared to the external environment. This contrasted with the results of the control home where PM2.5 levels were higher than ambient levels. Whilst the results cannot be generalized, they do provide much needed evidence on the indoor environmental performance of a Passivhaus-certified dwelling in Latin America, highlighting areas for improvement and providing recommendations to help inform future developments adopting these principles in a subtropical highland climate.
Ethiopia is endowed with water and has a high runoff generation area compared to many countries, but the total stored water only goes up to approximately 36BCM. The problem of water shortage in Ethiopia emanates from the seasonality of rainfall and the lack of infrastructure for storage to capture excess runoff during flood seasons. Based on this premise, a method for a syndicate use of topography, land use and vegetation was applied to locate potential surface water storing sites. The steady-state Topographic Wetness Index (TWI) was used to represent the spatial distribution of water flow and water stagnating across the study area and the Normalized Difference Vegetation Index (NDVI) was used to detect surface water through multispectral analysis. With this approach, a number of water storing sites were identified in three categories: primary sources (water bodies based), secondary sources (Swampy/wetland based) and tertiary sources (the land based). A sample volume analysis for the 120354 water storing sites in category two, gives a 44.92BCM potential storing capacity with average depth of 4 m that improves the annual storage capacity of the country to 81BCM (8.6 % of annual renewable water sources). Finally, the research confirmed the TWI and NDVI based approach for water storing sites works without huge and complicated earth work; it is cost effective and has the potential of solving complex water resource challenges through spatial representation of water resource systems. Furthermore, the application of remote sensing captures temporal diversity and includes repetitive archives of data, enabling the monitoring of areas, even those that are inaccessible, at regular intervals.
Soil erosion is one of the major environmental threats in the northwestern Amhara Region of Ethiopia. The objective of this study is to assess the spatial heterogeneity of soil erosion risk within the Gumara-Maksegnit watershed (57.3 km2) using the Coordination of Information on the Environment (CORINE) soil erosion assessment method to determine the most endangered areas. The model is simple and robust and consists of six steps overlaying combinations of soil texture, depth, stoniness, climatic and land-use/land-cover information with GIS support. The CORINE model was used to produce potential and actual soil erosion maps. The potential soil erosion map consists of the erosion risk of the land without considering current vegetation, but can be expanded to consider current land cover. The potential soil erosion risk map showed that a small part of the watershed (6.63 %) had low risk, 17.92 % had moderate risk and a large part of the study area (75.45 %) had high potential erosion risk. Meanwhile, the actual soil erosion risk map showed that a small part of the watershed (11.92 %) had low risk, 20.85 % of the area had moderate risk, and a large part of the study area (67.23 %) had high actual soil erosion risk. Low soil erosion risk areas were located in the southern part of the watershed, high erosion risk areas were found in the northern, northwestern and eastern part of the watershed, while moderately risky areas were randomly distributed throughout the watershed. Overall, the CORINE model can play a role in soil and water conservation by identifying highly endangered areas.
The traditional approach of landscape architecture has always focused on the aesthetic and visual aspects of landscapes while giving less attention to other aspects. This view has limited the benefits that can be derived from designed landscapes, despite the wide-ranging potential they carry for humans; socially, environmentally and economically. As a result, many researchers and practitioners are currently challenging this view to develop a more holistic and multidimensional approach. The present research therefore aims at proposing a new perspective for public designed landscapes based on fundamental human needs. The study methodology was comprised of critical content analysis for three main domains: sustainable development, human needs in specific relation to public landscapes, and significant approaches to fundamental human needs. Reconciliation among these domains was achieved based on a modified version of Max-Neef’s matrix of fundamental human needs. Human needs in public landscapes were merged into the matrix to reach a comprehensive yet specific perspective. The study concluded with a conceptual framework that can provide a wider perspective to human needs in designed landscapes. It proposes a new tool for the analysis of the benefits of public landscapes and their value for humans, which can be further used in various applications.
Droughts threaten many regions worldwide, in particular semi-arid environments of sub-Saharan Africa such as the Cuvelai-Basin in Angola and Namibia, as the population depends on critical water-related ecosystem services. Since droughts are multi-layered phenomena, risk assessment tools that capture the societal relations to nature and identify those individuals that are most threatened are required. This study presents the integrated Household Drought Risk Index (HDRI) that builds upon empirical data from the study area to provide insights into drought hazard and vulnerability conditions of households in different socio-economic and environmental settings. The composite indicator integrates environmental measures of drought (frequency, severity, duration) from multiple remote sensing products (precipitation, soil moisture, vegetation) and the vulnerability of households (sensitivity, coping capacity) obtained from a structured survey that comprised 461 households. The results reveal that the Angolan population shows higher levels of risk, particularly caused by less developed infrastructural systems, weaker institutional capabilities and less coping capacities. Overall, urban dwellers follow less drought-sensitive livelihood strategies, but are still connected to drought conditions in rural areas due to family relations with obligations and benefits. The study results provide knowledge for decision-makers to respond to drought in the short and long-term. The latter may build upon the extension of centralized and decentralized water and food supply/production systems as well as the support of households via targeted educational and community-building measures. Specific HDRI components may be included in census surveys to receive continuous drought risk data.
