Balancing Ecological and Economic Objectives in Land Use and Management: Modeling to Identify Sustainable Spatial Patterns.

Human-driven land-use/cover (LULC) changes threaten the integrity of ecosystems in many ways. To evaluate possible impacts of future changes in LULC on ecosystem services and support more sustainable environmental management, it is essential to understand how land-use patterns affect both ecological and economic outcomes, and how alternative spatial land-use and -management strategies may improve sustainability in land-use systems. I developed and tested a spatial simulation approach that can help improve our understanding of how human-driven landscape conditions at the watershed scale might reshape impacts on both water quality and economic performance in a Lake Erie watershed under a changing climate. The dissertation is organized into three chapters. The first chapter describes a study in which I evaluated sensitivity of a stochastic land-change model (LCM) to pixel versus polygonal land unit derived from parcel maps. Performance of pixel- and polygon-based simulations suggest that using polygonal unit is helpful with generating more realistic landscape patterns, but at the cost of spatial allocation accuracy. For the second chapter, I developed the first integrated modeling approach that compares the relative economic efficiency of alternative spatial land-use and -management strategies for addressing non-point source (NPS) nutrient pollution. Using the Soil Water Assessment Tool (SWAT) and data on crop costs and prices, I evaluated joint impacts on nutrient reduction and economic returns for optimized patterns of land-use changes (LUCs) versus conservation practices (CPs) at the field scale. Simulated results showed relying on CPs alone might not be sufficient to restore water quality in Lake Erie, and a combination strategy including both LUCs and CPs would be necessary and more efficient. Finally, I examined sensitivity of optimized spatial patterns of land-use and -management (CPs) approaches to climate change. I found optimal land-use and -management placement can be quite sensitive to change in climatic conditions. CP targeting was found to be more robust to climate change than land-use change, but integration of both strategies would be necessary to achieve high DRP reduction (>65%) targets. Results from this study highlight the need for future spatial optimization studies to consider adaptive capacity of conservation actions under a changing climate.PhDNatural Resources and EnvironmentUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/133330/1/xuhui_1.pd

Modeling the spatial and temporal trends of water quality in boreal managed watersheds

Land use changes have altered natural hydrological pathways and biogeochemical cycling of carbon, nitrogen and phosphorus, among other elements, affecting the quality of aquatic ecosystems such as rivers, lakes and coastal areas. In this dissertation, the spatial and temporal trends of water quality variation in Finnish managed watersheds was studied by applying methods of multivariate statistics, time-series analysis, ecohydrological modeling and high-resolution geospatial data. The results show the complex effects of current land use, particularly agriculture, on stream water quality. New emerging trends of nutrient concentrations and loads were detected in the time-series analysis, such as an increase in the concentrations and loads of dissolved reactive phosphorus and total nitrogen, and a decrease in suspended sediment concentration in streams. This might be linked to the current erosion reduction strategy of land management for water protection. An ecohydrological modeling assessment showed an increasing downstream nutrient export from agricultural watershed under climate change scenarios. The modeling results also showed a potential nutrient export reduction by restoring potential biogeochemical hotspot areas - wet areas or areas prone to water saturation. These areas can function as nutrient sinks and enhance the watershed resiliency. High-resolution geospatial data allowed easier and more accurate mapping of wet areas as well as the extracting of their hydraulic characteristics. However, the ecohydrological models involved several sources of uncertainties, which need to be carefully addressed with extensive observational data, expert knowledge of model parameter definitions, proper modeling unit selection and empirical knowledge of the functioning of the studied watershed system. The results of this dissertation highlight the importance of combined methods for watershed management research, and the proper identification of the biophysical processes in the modeling of non-point pollutant sources; this can in turn lead to an efficient water protection measure, and restoring biogeochemical hotspot areas within the watershed.Vedenlaadun alueellisten ja ajallisten vaihteluiden mallintaminen viileän vyöhykkeen valuma-alueilla. Maankäytön muutokset ovat vaikuttaneet luonnollisiin hydrologisiin prosesseihin sekä hiilen, typen ja fosforin biogeokemiallisiin kiertoihin. Nämä puolestaan vaikuttavat vesiekosysteemien tilaan joissa, järvissä ja rannikkoalueella. Väitöstutkimuksessa tutkittiin vedenlaadun alueellisia ja ajallisia muutoksia suomalaisessa maaseutumaisemassa käyttäen monimuuttujamenetelmiä, aikasarja-analyysejä, ekohydrologista mallinnusta ja erotuskyvyltään tarkkoja paikkatietoaineistoja. Tulokset todentavat maatalouteen kytkeytyvien maankäytön piirteiden kompleksisia vaikutuksia jokivesien laatuun. Aikasarja-analyysit osoittivat myös aiemmin tuntemattomia trendejä jokivesien ravinteiden määrissä ja pitoisuuksissa, esimerkkeinä liuenneen reaktiivisen fosforin määrän ja pitoisuuden lisääntyminen sekä sedimenttisuspension väheneminen; molemmat eroosion vähentämiseen tähtäävien vesiensuojelutoimien seurauksena. Ekohydrologinen mallinnus osoitti myös sen, että ravinteiden huuhtoutuminen maatalousvaltaisilla valuma-alueilla lisääntyy ilmastonmuutoksen seurauksena. Tulokset kannustavat biogeokemiallisten avainalueiden, kuten kosteikkojen ja vettä keräävien painanteiden kunnostamiseen, jolloin ravinteiden huuhtoutuminen vähenee. Ravinnenieluina toimiessaan ne voivat myös parantaa valumaalueen ekologista kestävyyttä ja palautumiskykyä. Tutkimuksessa osoitettiin myös erotuskyvyltään tarkkojen paikkatietoaineistojen hyödyllisyys avainalueiden kartoituksessa ja alueiden hydrologisten ominaisuuksien tunnistamisessa. Ekohydrologiseen mallinnukseen sisältyy toisaalta myös epävarmuustekijöitä, joihin tulisi paneutua vielä kattavammin hyödyntäen asiantuntijatietoa parametrien täsmentämisessä, määrittämällä tarkennettuja mallinnusyksiköitä tai hyödyntäen empiirisiä tutkimustietoja valuma-alueen toiminnasta. Väitöstutkimus osoittaa myös sen, miten erilaisten tutkimusmenetelmien yhdistely vahvistaa valuma-aluetarkastelua ja siihen liittyen erilaisten biofysikaalisten prosessien ymmärtämistä ja keskeisten päästölähteiden mallintamista. Näin muodoin yhdistelmämenetelmien käyttö tukee entistä tehokkaampien vesiensuojelutoimien kehittämistä ja valumaalueiden biogeokemiallisten avainalueiden kunnostamistaModelado de las tendencias temporales y espaciales de la calidad del agua en cuencas hidrográficas boreales manejados. El cambio del uso del suelo ha alterado los procesos hidrológicos naturales y los ciclos biogeoquímicos del carbono, el nitrógeno y el fósforo, entre otros elementos, afectando directamente la calidad de los ecosistemas acuáticos como los ríos, lagos y zonas costeras. En esta disertación, las tendencias espaciales y temporales de la variación de la calidad del agua en cuencas hidrográficas finlandesas se estudiaron mediante la aplicación de métodos de estadística multivariante, análisis de series de tiempo, modelos ecohidrológicos y datos geoespaciales de alta resolución. Los resultados muestran los efectos complejos del uso actual del suelo, particularmente la agricultura, en la calidad del agua de los ríos y corrientes. Se detectaron nuevas tendencias emergentes de concentraciones y cargas de nutrientes en el análisis de series temporales, como un aumento en la concentración y carga del fósforo disuelto reactive y nitrógeno total, y una disminución en la concentración de sedimentos en suspensión en los ríos y corrientes. Esto podría estar vinculado a la estrategia actual de manejo del suelo, orientado a la reducción de la erosión para la protección del agua. Una evaluación a través de modelización ecohidrológica mostró un aumento de la exportación de nutrientes aguas abajo de la cuenca agrícola bajo escenarios de cambio climático. Los resultados de la modelización también mostraron una posible reducción de la exportación de nutrientes mediante la restauración de posibles zonas críticas biogeoquímicas: áreas húmedas o áreas propensas a la saturación de agua. Estas áreas pueden funcionar como sumideros de nutrientes y mejorar la resiliencia de la cuenca. Los datos geoespaciales de alta resolución permitieron un fácil y más preciso cartografiado de las áreas húmedas, así como la extracción de sus características hidráulicas. Sin embargo, los modelos ecohidrológicos involucraron varias fuentes de incertidumbre, que deben abordarse cuidadosamente con bastantes datos de observación, conocimiento experto de las definiciones de los parámetros del modelo, selección adecuada de la unidad de modelado y conocimiento empírico del funcionamiento del sistema de la cuenca estudiada. Los resultados de esta disertación destacan la importancia de los métodos combinados para la investigación de gestión de cuencas hidrográficas y la identificación adecuada de los procesos biofísicos en la modelización de fuentes contaminantes difusas; esto a su vez puede conducir a una medidaeficiente de protección del agua, y restauración de áreas claves de alta función biogeoquímica dentro de la cuenca

Advanced decision support methods for solving diffuse water pollution problems

Dealing with water diffuse pollution is a major problem for watershed managers. This problem raises many complicated questions, which are important to answer in order to reach water environment protection goals. This study suggested some possible answers for the country of Lithuania. Among them were the identification of critical source areas, the identification of sensitive areas and the application of multi-objective spatial optimization. Those decision support methods were not only suggested, but also examined through literature review and their application was demonstrated practically on the Graisupis river catchment, which is located in the middle of Lithuania. For this purpose, the SWAT (Soil and Water Assessment Tool) model was prepared and successfully calibrated and validated for water flows and nitrate load simulations. The model was calibrated for 7 years (2000-2006) and validated for 3 years period (2007-2009). The model was run for 10 years period (2000-2009) in order to obtain results for decision support methods. Critical source areas were defined as those areas, which have nitrate loads to surface water bodies higher by two standard deviations from average in the catchment. Sensitivity (nutrient leaching potential) of areas was assigned based on the response of modeled physical nature to the addition of nitrogen fertilizers. The SWAT model was also used for the simulation of effects of best environment practices. The results were imported into the genetic algorithm, which was used for the purposes of multi-objective spatial optimization. Model results indicated average nitrate loading of 15.9 kg nitrate nitrogen per hectare in the catchment. The identification of critical source areas located 12.4% of the Graisupis river catchment as risk areas. The sensitive areas identification assigned medium or low sensitivity to 99.5% of the catchment. Only 0.4% of the catchment territory was identified as high or very high sensitivity. Multi-objective spatial optimization increased the costeffectiveness of diffuse pollution abatement 24 times (up to 50 times with lesser implementation scale), if compared to the random selection of best environmental practices. Optimization with equal weights for environmental and economic objectives resulted in 16.9 LTL for reduction of 1 kg nitrate nitrogen to surface water bodies, while providing 62% reduction of total loads to surface water bodies. This scenario required 24% of additional catchment territory to be converted to grasslands and consideration of filter strips for 34% of the catchment territory. Optimization for obtaining Pareto optimum between environmental and economic objectives provided the most cost effective solution of 9.7 LTL for reduction of 1 kg nitrate nitrogen, while providing 25% reduction of total loads to surface water bodies. This scenario required the application of cover crops on 2.6%, new grasslands on 1.6% and consideration of filter strips on 11% of the Graisupis river catchment area. Optimization for obtaining Pareto optimum between environmental and economic objectives also provided quantifiable relationship between economic and environmental objectives in the form of regression equation

Analysis of land use changes and water resources in lowland catchments of Northern Germany

With increasing pressures from natural disturbances and anthropogenic activities, water quality is degraded and sustainable management becomes more challenging. A good understanding of the key influential factors for water resources will help to develop effective catchment management plans for addressing water resources issues. However, a systematic assessment of cause-effect relationships between land use and water quality or quantity is still rare, particularly across different temporal and spatial scales. This study aims to explore the spatially distributed catchment variables controlling landscape patterns, and to identify the important catchment characteristics and spatial scales for explaining the water quality or quantity dynamics. The rural lowland catchments (namely Kielstau and Stör) in Northern Germany were selected as study areas. Intensive field campaigns have been carried out in the two catchments: land use mapping in both catchments and a water quality campaign (2018-2019) in the Stör catchment that complements campaigns from 1992-1994 and 2009-2011. Different multivariate statistics and a hydrological modelling (SWAT) approach have been applied. The distribution patterns of each specific land use class were identified based on logistic regression analysis using spatially distributed variables. Furthermore, stepwise multiple linear regression (SMLR) and redundancy analyses (RA) were applied to investigate influences of main categories of catchment characteristics on water quality at multiple spatial and temporal scales. The SWAT model was calibrated and validated for modeling the dynamic processes of streamflow, sediment, total phosphorus (TP), and total nitrogen (TN). The variabilities in main water balance components and nutrients in response to varied landscape patterns were investigated by applying the integrated approach of SWAT modeling and partial least squares regression model (PLSR)

Assessing the Influence of Land Use and Land Cover Datasets with Different Points in Time and Levels of Detail on Watershed Modeling in the North River Watershed, China

National Natural Science Foundation of China [40901100, 40810069004]Land use and land cover (LULC) information is an important component influencing watershed modeling with regards to hydrology and water quality in the river basin. In this study, the sensitivity of the Soil and Water Assessment Tool (SWAT) model to LULC datasets with three points in time and three levels of detail was assessed in a coastal subtropical watershed located in Southeast China. The results showed good agreement between observed and simulated values for both monthly and daily streamflow and monthly NH4+-N and TP loads. Three LULC datasets in 2002, 2007 and 2010 had relatively little influence on simulated monthly and daily streamflow, whereas they exhibited greater effects on simulated monthly NH4+-N and TP loads. When using the two LULC datasets in 2007 and 2010 compared with that in 2002, the relative differences in predicted monthly NH4+-N and TP loads were -11.0 to -7.8% and -4.8 to -9.0%, respectively. There were no significant differences in simulated monthly and daily streamflow when using the three LULC datasets with ten, five and three categories. When using LULC datasets from ten categories compared to five and three categories, the relative differences in predicted monthly NH4+-N and TP loads were -6.6 to -6.5% and -13.3 to -7.3%, respectively. Overall, the sensitivity of the SWAT model to LULC datasets with different points in time and levels of detail was lower in monthly and daily streamflow simulation than in monthly NH4+-N and TP loads prediction. This research provided helpful insights into the influence of LULC datasets on watershed modeling

False positive and false negative errors in the design and implementation of agri-environmental policies: a case study on water quality and agricultural nutrients

When designing and implementing agri-environmental policies to reduce nutrient loss, action programmes may falsely address areas where the nutrient issue from agricultural activity is not currently important and is not likely to become so in the future (a false positive), or may fail to address areas where the agricultural nutrient issue is currently important or may likely become so in the future (a false negative). Based on a case study of the Louros watershed in Greece, this work identifies database and modelling sources of false positives and negatives and proposes a decision making process aimed at minimizing the possibility of committing such errors. The baseline is well simulated and shows that the Louro’s watershed falls behind a Good Environmental Status, at least marginally. Simulated mitigation measures show that the river’s status can be upgraded to “Good”, at least as concerns nitrates and ammonium. Simulated climate change does not seem to exert an important positive or negative effect. Land use changes forecasting considerably less cultivated area have a significant effect on Total Phosphorous but not on nitrates or ammonium concentrations. The non-linearity between nutrient disposition (inputs) and nutrient concentration in downstream water bodies (output) and the many factors that affect the nutrient disposition-transportation-concentration chain, highlights the importance of simulating the effects of mitigation actions and of future climate and land use changes before adopting and establishing agri-environmental measures

Application of a Spatially Explicit, Agent-Based Land Use Conversion Model to Assess Water Quality Outcomes under Buffer Policies

Land use changes within watersheds have spatially explicit dynamics and involve decision making by individuals. The role of the spatial dimension of human behavior and its impact on land use change has been analyzed using agent-based modelling approaches. Agent-based land use change has received a significant theoretical attention; however, these models lack empirical implementation and testing due to the lack of spatial modelling tools and data that can capture human land use dynamics.;This research presents a methodology for projecting land use conversions through the implementation of a spatially explicit agent-based simulation model in the Opequon Creek watershed of Berkeley County, West Virginia. Empirical estimates for factors that influence the land use conversion probability are captured using a spatial logistic regression model. Then, agentbased probabilistic land use conversion (APLUC) model is programmed on Python language within a geographic information system (GIS) to explore the impacts of policies on land use conversion decisions using estimates from actual land use change from 2001-2011. A series of model runs are executed under buffer policy scenarios. Three policy scenarios are developed: (1) a scenario where there is no policy implemented, (2) a scenario where 50 ft buffer zones are applied to all streams, and (3) a scenario where 50 ft buffers are applied only on critical source areas (CSAs) watersheds. The land use patterns project in APLUC model are driven by individual land conversion decisions over 50 model runs of 10 iterations each under each policy scenario. The APLUC model is validated at sub-basin level and outcomes are analyzed to identify the influence of various land use policies on land use patterns. The results show that a 50 ft buffer policy everywhere in watershed, greatly reduced the residential land use conversions. Spatial patterns generated under a 50 ft buffer policy in CSAs only showed that future projected land use changes occurred close to major highways. In the baseline policy, most conversions occurred near existing residential land use and urban centers. Results from the APLUC model also suggests that forest is serving as distant amenity for residential land conversion.;Finally, the impacts of these three policies on water quality are estimated using an ArcSWAT model, a graphical user interface for SWAT (Soil and Water Assessment Tool). This model indicates that the 50 ft buffer policy in CSAs is most effective among the three policies in reducing the pollutant loads. This study suggests that carefully designed policies, which discourage residential land use conversion in CSAs, result in less pollutant loads by shifting the location of residential conversion to less critical areas where agricultural land is dominant in the watershed

FOUR DECADES OF HYDROLOGICAL PROCESS SIMULATION OF THE ITACAIÚNAS RIVER WATERSHED, SOUTHEAST AMAZON

The impacts of anthropogenic degradation are becoming increasingly more evident in the Amazon and are jeopardizing its environmental systems and water resources, particularly in low monitored watersheds. Thus, the use of hydrological models is necessary to gain an understanding of these impacts on Amazonian river systems. The aim of this study was to analyze the simulation of some hydrological processes in the Itacaiúnas River watershed and its relation with human-induced impacts in the Southeast region of the Pará state using the Soil and Water Assessment Tool (SWAT) model. SWAT modeling requires several databases, such as relief, land use and land occupation, soil type, and climatic and hydrological variables. These data are input parameters for the SWAT model. The results showed that the hydrological variables in the Amazon tend to follow the seasonal precipitation cycle, with the highest values occurring between January and June and lowest between July and November. It was evident that base and lateral flows are responsible for maintaining perennial river flow during the dry season. Regarding anthropogenic actions in the watershed, precipitation, evapotranspiration, and sediment transportation are clearly affected by environmental degradation, as well as by the replacement of forest by grassland and mining activities. The results may assist in public policy including mitigation and adaptation of environmental systems in the region. In addition, they can improve the management of natural resources in the Itacaiúnas River watershed