Trajectory analysis of land use and land cover maps to improve spatial-temporal patterns, and impact assessment on groundwater recharge

© 2017 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 24 month embargo from date of publication (Sept 2017) in accordance with the publisher’s archiving policyLand use/land cover (LULC) change is a consequence of human-induced global environmental change. It is also considered one of the major factors affecting groundwater recharge. Uncertainties and inconsistencies in LULC maps are one of the difficulties that LULC timeseries analysis face and which have a significant effect on hydrological impact analysis. Therefore, an accuracy assessment approach of LULC timeseries is needed for a more reliable hydrological analysis and prediction. The objective of this paper is to assess the impact of land use uncertainty and to improve the accuracy of a timeseries of CORINE (coordination of information on the environment) land cover maps by using a new approach of identifying spatial–temporal LULC change trajectories as a pre-processing tool. This ensures consistency of model input when dealing with land-use dynamics and as such improves the accuracy of land use maps and consequently groundwater recharge estimation. As a case study the impact of consistent land use changes from 1990 until 2013 on groundwater recharge for the Flanders-Brussels region is assessed. The change trajectory analysis successfully assigned a rational trajectory to 99% of all pixels. The methodology is shown to be powerful in correcting interpretation inconsistencies and overestimation errors in CORINE land cover maps. The overall kappa (cell-by-cell map comparison) improved from 0.6 to 0.8 and from 0.2 to 0.7 for forest and pasture land use classes respectively. The study shows that the inconsistencies in the land use maps introduce uncertainty in groundwater recharge estimation in a range of 10–30%. The analysis showed that during the period of 1990–2013 the LULC changes were mainly driven by urban expansion. The results show that the resolution at which the spatial analysis is performed is important; the recharge differences using original and corrected CORINE land cover maps increase considerably with increasing spatial resolution. This study indicates that improving consistency of land use map timeseries is of critical importance for assessing land use change and its environmental impact

Spatiotemporal Changes of Farming-Pastoral Ecotone in Northern China, 1954–2005: A Case Study in Zhenlai County, Jilin Province

Analyzing spatiotemporal changes in land use and land cover could provide basic information for appropriate decision-making and thereby plays an essential role in promoting the sustainable use of land resources, especially in ecologically fragile regions. In this paper, a case study was taken in Zhenlai County, which is a part of the farming-pastoral ecotone of Northern China. This study integrated methods of bitemporal change detection and temporal trajectory analysis to trace the paths of land cover change for every location in the study area from 1954 to 2005, using published land cover data based on topographic and environmental background maps and also remotely sensed images including Landsat MSS (Multispectral Scanner) and TM (Thematic Mapper). Meanwhile, the Lorenz curve and Gini coefficient derived from economic models were also used to study the land use structure changes to gain a better understanding of human impact on this fragile ecosystem. Results of bitemporal change detection showed that the most common land cover transition in the study area was an expansion of arable land at the expense of grassland and wetland. Plenty of grassland was converted to other unused land, indicating serious environmental degradation in Zhenlai County during the past decades. Trajectory analysis of land use and land cover change demonstrated that settlement, arable land, and water bodies were relatively stable in terms of coverage and spatial distribution, while grassland, wetland, and forest land had weak stability. Natural forces were still dominating the environmental processes of the study area, while human-induced changes also played an important role in environmental change. In addition, different types of land use displayed different concentration trends and had large changes during the study period. Arable land was the most decentralized, whereas forest land was the most concentrated. The above results not only revealed notable spatiotemporal features of land use and land cover change in the time series, but also confirmed the applicability and effectiveness of the methodology in our research, which combined bitemporal change detection, temporal trajectory analysis, and a Lorenz curve/Gini coefficient in analyzing spatiotemporal changes in land use and land cover

Representation of seasonal land use dynamics in SWAT+ for improved assessment of blue and green water consumption

This research article was published by Hydrology and Earth System Sciences, 2022In most (sub)-tropical African cultivated regions, more than one cropping season exists following the (one or two) rainy seasons. An additional cropping season is possible when irrigation is applied during the dry season, which could result in three cropping seasons. However, most studies using agro-hydrological models such as the Soil and Water Assessment Tool (SWAT) to map blue and green evapotranspiration (ET) do not account for these cropping seasons. Blue ET is a portion of crop evapotranspiration after irrigation application, while green ET is the evapotranspiration resulting from rainfall. In this paper, we derived dynamic and static trajectories from seasonal land use maps to represent the land use dynamics following the major growing seasons to improve simulated blue and green water consumption from simulated evapotranspiration in SWAT+. A comparison between the default SWAT+ set-up (with static land use representation) and a dynamic SWAT+ model set-up (with seasonal land use representation) is made by a spatial mapping of the ET results. Additionally, the SWAT+ blue and green ET were compared with the results from the four remote sensing data-based methods, namely SN (Senay), EK (van Eekelen), the Budyko method, and soil water balance method (SWB). The results show that ET with seasonal representation is closer to remote sensing estimates, giving higher performance than ET with static land use representation. The root mean squared error decreased from 181 to 69 mm yr−1, the percent bias decreased from 20 % to 13 %, and the Nash–Sutcliffe efficiency increased from −0.46 to 0.4. Furthermore, the blue and green ET results from the dynamic SWAT+ model were compared to the four remote sensing methods. The results show that the SWAT+ blue and green ET are similar to the van Eekelen method and performed better than the other three remote sensing methods. It is concluded that representation of seasonal land use dynamics produces better ET results, which provide better estimations of blue and green agricultural water consumption

How Can We Represent Seasonal Land Use Dynamics in SWAT and SWAT+ Models for African Cultivated Catchments?

This research article published by MDPI, 2020In SWAT and SWAT+ models, the variations in hydrological processes are represented by Hydrological Response Units (HRUs). In the default models, agricultural land cover is represented by a single growing cycle. However, agricultural land use, especially in African cultivated catchments, typically consists of several cropping seasons, following dry and wet seasonal patterns, and are hence incorrectly represented in SWAT and SWAT+ default models. In this paper, we propose a procedure to incorporate agricultural seasonal land-use dynamics by (1) mapping land-use trajectories instead of static land-cover maps and (2) linking these trajectories to agricultural management settings. This approach was tested in SWAT and SWAT+ models of Usa catchment in Tanzania that is intensively cultivated by implementing dominant dynamic trajectories. Our results were evaluated with remote-sensing observations for Leaf Area Index (LAI), which showed that a single growing cycle did not well represent vegetation dynamics. A better agreement was obtained after implementing seasonal land-use dynamics for cultivated HRUs. It was concluded that the representation of seasonal land-use dynamics through trajectory implementation can lead to improved temporal patterns of LAI in default models. The SWAT+ model had higher flexibility in representing agricultural practices, using decision tables, and by being able to represent mixed cropping cultivations

Temporary analysis of land use changes in Pine and mixed forests in Mexico

Objective: To assess the surface changes that occurred in pine forests, mixed forests and secondary vegetation of pine and mixed forests, at the national level, during the period 2001 to 2013. Design/methodology/approach: We used the Land Use and Vegetation (USV) coverages of Series II (from 2001) and V (from 2013) of the National Institute of Statistics and Geography, of scales 1: 250,000 as primary sources of information. The classes on both coverages were grouped and homogenized, focusing on pine and mixed forests. The exchange rates and transition indicators were estimated for the analysis: estimated profit and loss surfaces, persistence indices, of exchanges and net changes, as well as the gain and loss indices to persistence. Results: The rate of changes are negative for primary forests (pine and mixed) is in a range of 0.80 to 1.84. It was observed that 120,047 km2 (57.72%) were stable surfaces; however, 36 986 km2 (18.00%) were from losses, 14 369 km2 from gains and 28 738 km2 (14.00%) from different categories. During the period analyzed, 13.69% of the primary forests(2001)  passed to secondary vegetation in 2013. Study limitations/implications: To observe the influence of other categories, it would be important to incorporate them through the study to analyze the system globally through the country. Findings/Conclusions: The persistence area of primary forests is important for generating conservation policies.Objective: to evaluate the changes in land use that occurred in Pine and mixed forests, at the national level during the period 2001 to 2013.Design/Methodology/Approach: layers of Land Use and Vegetation (Sp. equ. USV) of Series II (from 2001) and V (from 2013) of the Instituto Nacional de Estadística y Geografía, scale 1: 250,000 were used. Different categories of vegetation under study were reclassified and homogenized for both covers. Rates of change and indicators of transitions were estimated for the spatial-temporary analysis: surfaces of estimated losses and gains, indices of persistence, exchanges and net changes; also, indices of gain and loss to persistence.Results: the rate of negative change for primary forests (Pine and mixed) ranges from 0.80 to 1.84. It was observed that 120 047 km2 (57.72%) were stable surfaces. However, 36 986 km2 (18.00%) were losses, 14 369 km2 gains and 28 738 km2 (14.00%) between categories. It was observed from 2001 to 2013 that 13.69% of the area corresponding to primary forests which existed in 2001 became part of secondary vegetation in 2013.Study limitations/Implications: in order to observe the influence of other categories, it would be important to incorporate more classes throughout the study to be analyzed globally in the system throughout the country.Findings/Conclusions: The persistence of the coverage of primary forests is important to design conservation policie

The Impact of Spatial Decision Variables Influencing Crop Rotation on Phosphorus Load Reduction: A Hydrologic Modeling Approach

Non-point source anthropogenic nutrient loading through intensive farming practices is a global source of water quality degradation by creating harmful algal blooms in aquatic ecosystems. Phosphorus, as the key nutrient in this process, has received much attention in different studies as well as conservation programs aimed at mitigating the transfer of polluting nutrients to freshwater resources. Central to conservation initiatives developed to maintain and improve water quality is the application of the Conservation Practices (CPs), introduced widely as practical, cost-effective measures with overall positive impacts on the rate of nutrient load reductions from farmlands to freshwater resources. Crop rotation is one of the field-based BMPs applied to maintain the overall soil fertility and preventing the displacement of the topsoil layers by surface water runoff across the agricultural watersheds. The underlying concept in the application of this particular BMP is a deviation from the monoculture cropping system by integrating different crops into the farming process. This way, cultivated soils do not lose key nutrients, which are necessary for crop growth, and the overall crop productivity remains unchanged in the landscape. The successful implementation of crop rotation highly depends on planning the rotation process, which is influenced by a variety of environmental, structural, and managerial factors, including the size of farmlands, climate variability, crop type, level of implementation, soil type, and market prices among other factors. Each of these decision variables is subject to variation depending upon the variability of other factors, the complexity of watersheds upon which this BMP is implemented, and the overall objectives of the BMP adoption. This study aims to investigate two of these decision variables and their potential impacts on phosphorus load reductions through a scenario-based hydrologic modeling framework developed to iv assess the post-crop rotation water quality improvements across the Medway Creek Watershed, situated in the Lake Erie Basin in Ontario, Canada. These variables are the spatial pattern of crop rotation and its level of implementation, assessed at the watershed scale through the modifications made to the delineation of the basic Hydrologic Response Units (HRUs) in the modeling process as well as certain assumptions in the management schedules, and decision rules required for the integration of crop rotation into the proposed modeling framework and optimal placement of this non-structural BMP across the watershed. The main modeling package utilized in this study is the Soil and Water Assessment Tool (SWAT), used in conjunction with the ArcGIS and IBMSPSS tools to allow for spatial assessment and statistical analyses of the proposed hydrologic modeling results, respectively. Following in-depth statistical analyses of the scenarios, the results of the study elicit the critical role of both factors by proposing optimal ranges of application on the watershed under study. Accordingly, to achieve optimal implementation results compared to the baseline scenario, which has the zero rate of implementation, conservation initiatives in the watershed are encouraged to consider the targeted placement of crop rotation on half of the lands under cultivation. Despite, having a statistically significant impact on water quality compared to the baseline scenario, the random distribution scenario is less effective than the targeted scenario in mitigation of total phosphorus load. Similarly, compared to the medium rate of implementation the targeted placement in a higher proportion of the cultivated areas did not lead to statistically significant results but may be considered depending upon the purpose and scope of implementation

Simulating Farmer Adoption of Agricultural Best Management Practices in the Upper Medway Creek Subwatershed

In the coupled human-environment system, humans play a central role in creating various environmental problems, and in turn, are impacted by these environmental consequences. In Canada, water quality degradation caused by agricultural activities has become a severe problem for a long time. It has been noted that the application of pesticides, manure and fertilizers have led to an increasing amount of chemicals and other pollutants in surface runoff which eventually converge into surface water bodies and result in water eutrophication. To maintain water quality and develop a sustainable agricultural system, Best Management Practices (BMPs) have been suggested. However, the high complexity of the agriculture system makes it difficult for policymakers and researchers to monitor and evaluate the performance of BMPs across large spatial scales and develop appropriate improvement strategies accordingly. Under these circumstances, agent-based models (ABM) stand out for their ability to deal with the complexities in the agri-environment system. To better understand the dynamics of farmer’s decision-making on BMP application under different socio-economic and environmental situations, an ABM has been developed to simulate the decision-making processes in the Upper Medway Creek subwatershed in this study. The ABM uses an optimizing decision-making structure that relies on choice by highest utility. In addition, the ABM integrates a weighted sum function to evaluate the influences of economic, environmental and social factors on farmers’ decision-making. Results from the model pre-test were compared to those obtained from a random generator to examine how does the developed ABM perform against the random generator. Then, a sensitivity analysis has been performed using the one-factor-at-a-time method to examine the impacts of different potential interventions, including government subsidies and educational activities, on farmers’ decision-making for certain BMP adoptions. The results demonstrated that the developed ABM is robust in simulating farmers’ decision-making on BMP application within the Upper Medway Creek subwatershed. According to the sensitivity analysis, providing subsidies and improving knowledge level of BMPs have positive effects on the implementations of certain BMPs in general. While comparing to improving knowledge levels of BMPs, providing subsidies makes greater contribution to motivating farmers to adopt BMPs. For each BMP, a subsidy rate, which indicates the proportion of implementation costs needs to be subsidized to effectively encourage the BMP adoption, has been suggested. The results of this study provide a better understanding of how different socio-economic conditions affect farmers’ decision-making on BMP adoptions and offer insights for policymakers to develop effective strategies incentivising farmers’ adoptions of BMPs and further preserving water quality in the Upper Medway Creek subwatershed

On the use of multi-sensor digital traces to discover spatio-temporal human behavioral patterns

134 p.La tecnología ya es parte de nuestras vidas y cada vez que interactuamos con ella, ya sea en una llamada telefónica, al realizar un pago con tarjeta de crédito o nuestra actividad en redes sociales, se almacenan trazas digitales. En esta tesis nos interesan aquellas trazas digitales que también registran la geolocalización de las personas al momento de realizar sus actividades diarias. Esta información nos permite conocer cómo las personas interactúan con la ciudad, algo muy valioso en planificación urbana,gestión de tráfico, políticas publicas e incluso para tomar acciones preventivas frente a desastres naturales.Esta tesis tiene por objetivo estudiar patrones de comportamiento humano a partir de trazas digitales. Para ello se utilizan tres conjuntos de datos masivos que registran la actividad de usuarios anonimizados en cuanto a llamados telefónicos, compras en tarjetas de crédito y actividad en redes sociales (check-ins,imágenes, comentarios y tweets). Se propone una metodología que permite extraer patrones de comportamiento humano usando modelos de semántica latente, Latent Dirichlet Allocation y DynamicTopis Models. El primero para detectar patrones espaciales y el segundo para detectar patrones espaciotemporales. Adicionalmente, se propone un conjunto de métricas para contar con un métodoobjetivo de evaluación de patrones obtenidos

O uso do sensoriamento remoto e da cartografia digital na gest?o de bacias hidrogr?ficas agr?colas.

Programa de P?s-Gradua??o em Evolu??o Crustal e Recursos Naturais. Departamento de Geologia, Escola de Minas, Universidade Federal de Ouro Preto.A partir do lan?amento dos primeiros sat?lites, a comunidade cient?fica tem tido acesso a novas ferramentas para enfrentar os v?rios problemas ambientais (espaciais), como por exemplo, degrada??o das florestas, eros?o dos solos, ?ndices como NDVI/SAVI/IAF, estimativa da evapotranspira??o, monitoramento de fen?menos clim?ticos e uso da terra. Todos estes ?par?metros? eram monitorados e /ou estimados somente com dados de campo, no entanto, as inova??es das geotecnologias como o sensoriamento remoto e a cartografia digital deram uma nova dimens?o para a compreens?o e resolu??o dos problemas ecol?gicos, clim?ticos e ambientais. Neste estudo, as tr?s sub-bacias de Entre Ribeiros (ET), Rio Escuro (RE) e Rio Verde (RV), localizadas na bacia hidrogr?fica do rio Paracatu, todas com ?reas superiores a 1000km2, est?o sob uma grande press?o de atividades agropecu?rias e silvicultura. Estas atividades envolvem o uso da ?gua do rio Paracatu e seus contribuintes, estando assim, os seus recursos h?dricos sobre uma grande demanda, necessitando para um monitoramento constante n?o s? da qualidade da ?gua, mas tamb?m da sua disponibilidade para as diversas atividades antr?picas e manuten??o dos ecossistemas aqu?ticos. Outro grande problema envolvendo estas ?reas ? susceptibilidade dos solos a processos erosivos, da? a grande necessidade do mapeamento das ?reas mais sens?veis a tais processos, para que assim se fa?a uma gest?o adequada dos mesmos. Com o intuito de desenvolver ferramentas num ambiente em SIG que permitir?o num futuro uma gest?o integrada de dados (estimativa da evapotranspira??o, qualidade da ?gua, uso do solo, eros?o do solo, qualidade de sedimentos fluviais) nestas tr?s sub-bacias, foram usadas v?rias geotecnologias. A evapotranspira??o (ET) foi estimada usando imagens de sat?lite MODIS ? MOD16 num per?odo de treze anos (2001 a 2014) e os resultados comparados com dados das escassas esta??es meteorol?gicas existentes nas tr?s sub-bacias. Os mapas anuais da ET demonstraram que os maiores valores se encontraram nas ?reas de silvicultura. A an?lise temporal da ET evidenciou um aumento progressivo ao longo de treze anos estudados. Os primeiros resultados das an?lises da qualidade da ?gua evidenciaram que as ?guas sofrem influ?ncia da atividade agr?cola, tendo sido encontrados em alguns pontos de amostragem concentra??es de metais pesados acima dos recomendados pela resolu??o CONAMA 357/05, colocando a ?gua nas classes 3 e 4. Para se identificar as ?reas mais suscept?veis ? eros?o foi criado um script baseado na equa??o USLE em ambiente SIG, que pode ser adicionado via ?Arctoolbox? no software ArcGIS. O modelo foi validado e mostrou-se eficaz na estimativa da eros?o nas tr?s sub-bacias em estudo. A cria??o do algoritmo, permitiu uma interface amig?vel no ambiente do ArcGIS, em que o usu?rio s? tem que adicionar as xx vari?veis da equa??o da USLE, e o software processar? os algoritmos automaticamente, gerando o mapa final com a perda do solo em T/ha.ano. No que diz respeito aos sedimentos fluviais os dados indicam contamina??o destes por metais pesados, tais como: As, Cd, Cr, Ni, Pb e Zn. Os mapas de uso e ocupa??o do solo quando cruzados com os mapas de concentra??o dos metais pesados permitiram inferir a origem prov?vel desses elementos nos sedimentos, pois os maiores valores ficaram registrados nas ?reas de silvicultura ou ? jusante dos piv?s de irriga??o. O uso conjunto do sensoriamento remoto e da cartografia digital na caracteriza??o e monitoramento destas tr?s sub-bacias demonstrou a sua elevada potencialidade na gest?o de grandes ?reas, devido ? robustez dos dados criados e ? facilita??o do entendimento dos problemas ambientais para os agentes p?blicos, empres?rios e popula??o em geral.Since the launch of the first satellites, scientific community has had access to new tools to address the various (space) environmental problems, such as forest degradation, soil erosion, index such as NDVI/SAVI/IAF, evapotranspiration calculations and the monitoring of climatic changes and land use. All these "parameters" were monitored and/or estimated only with field data, however, the innovations in geotechnologies, such as remote sensing and digital cartography, gave a new dimension to the understanding and resolution of ecological, climatic and environmental problems. In this study, the three sub-basins of Entre Ribeiros (ET), Rio Escuro (RE) and Rio Verde (RV), located in the Paracatu river basin, all covering areas over a 1000km2, are under great pressure due to agricultural, pasture and silviculture activities. These activities involve the use of water from the Paracatu River and other rivers and creeks, thus, their water resources are in great demand, necessitating constant monitoring not only for water quality, but also for water availability for the various anthropogenic activities and maintenance of aquatic ecosystems. Another major problem involving these areas is the susceptibility of soils to erosive processes, what demands the definition and location of the most sensitive areas to such processes, to enable a proper management. In order to develop tools in a GIS environment that will allow future integrated data management (estimation of evapotranspiration, water quality, soil use, soil erosion, quality of fluvial sediments) in these three sub-basins, several geotechnologies were used. The evapotranspiration (ET) was estimated using MODIS-MOD16 satellite images over a period of thirteen years (2001 to 2014) and the results compared with data from the scarce meteorological stations in the three sub-basins. The annual ET maps showed that the highest values were found in the silviculture areas. The temporal analysis of ET showed a progressive increase over the 13 years studied. The first results of the water quality analysis showed that the waters are influenced by agricultural activity, and at some sampling points concentrations of heavy metals were found above those recommended by CONAMA Resolution 357/05, placing the water in classes 3 and 4. To identify most susceptible areas to erosion, a script was created based on the USLE equation in GIS environment, which can be added via "Arctoolbox" in ArcGIS software. The model was validated and proved to be effective in estimating erosion in the three sub-basins studied. The creation of the algorithm allowed a user-friendly interface in the ArcGIS environment, in which the user has only to add the variables of the USLE equation, and the software will process the algorithms automatic, generating the final map with the soil loss in T/ha.year. In relation to fluvial sediments, the data indicate contamination of these materials by heavy metals, such as: As, Cd, Cr, Ni, Pb and Zn. The maps of land use and occupation when crossed with the maps of heavy metals xxii concentrations allowed inferring the probable origin of these elements in the sediments, since the highest values were registered in the silviculture areas or downstream of the irrigation pivots. The joint use of remote sensing and digital cartography in the characterization and monitoring of the three sub-basins demonstrated their high potential in managing large areas, due to the robustness of the data created and to facilitate stakeholders understanding of the environmental problems