Distribution Of Water Bodies Research Articles

Water Resources of Barak Valley, India: Spatial Assessment of Lentic and Lotic System Using Remote Sensing and GIS at 5.8 m Resolution

High resolution remote sensing data are suitable for quantifying or analyzing very small land cover components. In this study, the spatial distribution of water bodies and the perennial rivers of Barak valley were mapped and studied. Mapping was done for the first time using the high resolution IRS-R2 LISS4 FX data. The study adopted a hybrid technique incorporating supervised technique using the maximum likelihood algorithm and Visual Interpretation technique after ground validation. The river Barak along with its tributaries and sub-tributaries were identified and mapped. 16 tributaries and sub-tributaries have been mapped and reported for the first time after ground validation. This is a first detailed study on the spatial assessment of the waterbodies in this region. A total of 549 surface water bodies have been mapped and studied. The result indicated that the total area under water cover during dry season was ca 21,186 ha of the total geographical area of the study region. The study revealed that maximum numbers of the surface water bodies were between the sizes of 1 to 50 ha in area. Sone beel (wetland) was found to be the largest surface water body of the valley covering a total area of 1,348 ha. The final map composed represents the surface water of Barak valley and their spatial distribution. Thus, this paper may significantly help decision makers and researchers for sustainable water management, monitoring, controlling and planning development at local and regional scales.

Divergent trends of open-surface water body area in the contiguous United States from 1984 to 2016.

The contiguous United States (CONUS), especially the West, faces challenges of increasing water stress and uncertain impacts of climate change. The historical information of surface water body distribution, variation, and multidecadal trends documented in remote-sensing images can aid in water-resource planning and management, yet is not well explored. Here, we detected open-surface water bodies in all Landsat 5, 7, and 8 images (∼370,000 images, >200 TB) of the CONUS and generated 30-meter annual water body frequency maps for 1984-2016. We analyzed the interannual variations and trends of year-long water body area, examined the impacts of climatic and anthropogenic drivers on water body area dynamics, and explored the relationships between water body area and land water storage (LWS). Generally, the western half of the United States is prone to water stress, with small water body area and large interannual variability. During 1984-2016, water-poor regions of the Southwest and Northwest had decreasing trends in water body area, while water-rich regions of the Southeast and far north Great Plains had increasing trends. These divergent trends, mainly driven by climate, enlarged water-resource gaps and are likely to continue according to climate projections. Water body area change is a good indicator of LWS dynamics in 58% of the CONUS. Following the 2012 prolonged drought, LWS in California and the southern Great Plains had a larger decrease than surface water body area, likely caused by massive groundwater withdrawals. Our findings provide valuable information for surface water-resource planning and management across the CONUS.

Monitoring Flooding Damages in Vegetation Caused by Mining Activities Using Optical Remote Sensing

Ground removal during the mineral extraction in mine galleries provokes permanent changes in ground compacting during mine exploitation and after mine closure. In extreme cases, the loss of cohesion in ground layer over mines causes surface subsidence and eventually the emergence of flooded areas on the surface. Mining companies are obligated to the surveillance and mending of damages caused by the mines during and after the exploitation of the mine. For that reason, it is necessary to determine accurately if the causes of a flooding are related to their activity or to other causes. The objective of the present study is to locate mine-related flooding using a two-step workflow that involves remote sensing data. First, a screening on water bodies was applied using multispectral data at landscape level followed by a multi-temporal analysis to detect changes in the distribution of water bodies. A second step addressed the differentiation of mine-related flooded areas from other dynamic water bodies using high-resolution hyperspectral data over vegetation affected by flooding. The proposed workflow reduces costs of monitoring for mining companies by identifying potential flooding areas, while an exhaustive study can be done in few selected areas to assure the causes of the flooding using technology that is more sophisticated. Even though supervision by experts is required at some steps of the workflow, the proposed methods can be integrated in a geoportal to permit a broad spectrum of users the access to the information.

Comparison of American Fisheries Society (AFS) Standard Fish Sampling Techniques and Environmental DNA for Characterizing Fish Communities in a Large Reservoir

AbstractRecently, methods involving examination of environmental DNA (eDNA) have shown promise for characterizing fish species presence and distribution in waterbodies. We evaluated the use of eDNA for standard fish monitoring surveys in a large reservoir. Specifically, we compared the presence, relative abundance, biomass, and relative percent composition of Largemouth Bass Micropterus salmoides and Gizzard Shad Dorosoma cepedianum measured through eDNA methods and established American Fisheries Society standard sampling methods for Theodore Roosevelt Lake, Arizona. Catches at electrofishing and gillnetting sites were compared with eDNA water samples at sites, within spatial strata, and over the entire reservoir. Gizzard Shad were detected at a higher percentage of sites with eDNA methods than with boat electrofishing in both spring and fall. In contrast, spring and fall gillnetting detected Gizzard Shad at more sites than eDNA. Boat electrofishing and gillnetting detected Largemouth Bass at more sites than eDNA; the exception was fall gillnetting, for which the number of sites of Largemouth Bass detection was equal to that for eDNA. We observed no relationship between relative abundance and biomass of Largemouth Bass and Gizzard Shad measured by established methods and eDNA copies at individual sites or lake sections. Reservoirwide catch composition for Largemouth Bass and Gizzard Shad (numbers and total weight [g] of fish) as determined through a combination of gear types (boat electrofishing plus gillnetting) was similar to the proportion of total eDNA copies from each species in spring and fall field sampling. However, no similarity existed between proportions of fish caught via spring and fall boat electrofishing and the proportion of total eDNA copies from each species. Our study suggests that eDNA field sampling protocols, filtration, DNA extraction, primer design, and DNA sequencing methods need further refinement and testing before incorporation into standard fish sampling surveys.Received October 26, 2016; accepted June 9, 2017Published online August 10, 2017

PeRL: a circum-Arctic Permafrost Region Pond and Lake database

Abstract. Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role in Arctic wetland ecosystems by regulating carbon, water, and energy fluxes and providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global and regional scales. The Permafrost Region Pond and Lake (PeRL) database presents the results of a circum-Arctic effort to map ponds and lakes from modern (2002–2013) high-resolution aerial and satellite imagery with a resolution of 5 m or better. The database also includes historical imagery from 1948 to 1965 with a resolution of 6 m or better. PeRL includes 69 maps covering a wide range of environmental conditions from tundra to boreal regions and from continuous to discontinuous permafrost zones. Waterbody maps are linked to regional permafrost landscape maps which provide information on permafrost extent, ground ice volume, geology, and lithology. This paper describes waterbody classification and accuracy, and presents statistics of waterbody distribution for each site. Maps of permafrost landscapes in Alaska, Canada, and Russia are used to extrapolate waterbody statistics from the site level to regional landscape units. PeRL presents pond and lake estimates for a total area of 1. 4 × 106 km2 across the Arctic, about 17 % of the Arctic lowland ( < 300 m a.s.l.) land surface area. PeRL waterbodies with sizes of 1. 0 × 106 m2 down to 1. 0 × 102 m2 contributed up to 21 % to the total water fraction. Waterbody density ranged from 1. 0 × 10 to 9. 4 × 101 km−2. Ponds are the dominant waterbody type by number in all landscapes representing 45–99 % of the total waterbody number. The implementation of PeRL size distributions in land surface models will greatly improve the investigation and projection of surface inundation and carbon fluxes in permafrost lowlands. Waterbody maps, study area boundaries, and maps of regional permafrost landscapes including detailed metadata are available at https://doi.pangaea.de/10.1594/PANGAEA.868349.

Impact of release of <i>Neochetina</i> spp. on growth and density of water hyacinth <i>Eichhornia crassipes</i>

Water hyacinth (<em>Eichhornia crassipes</em>) is an invasive aquatic macrophyte which creates several problems in irrigation system of rivers. To control their rapid distribution in water bodies the biological control method was carried by employing weevils <em>Neochetina bruchi</em> and <em>Neochetina eichhorniae</em> on river based field trial. The study demonstrates effectiveness of biocontrol weevil open field release on experimental site (Chittar river). When compared to first release in field, the weevil intensity was increased in numbers. Active scraping was observed in the leaves and decay spots were seen in the stems of weed. Both <em>N. bruchi</em> and <em>N. eichhorniae</em> (250 No) were introduced biyearly at experimental site for one year. During these two years of observation period, stunted growth and reduced population were observed in the study site. The study highlights importance of <em>Neochetina</em> spp. on the management of <em>E. crassipes.</em>

Mosquito assemblages associated with urban water bodies; implications for pest and public health threats

Mosquitoes and mosquito-borne pathogens within urban regions may vary in response to short-term spatial and temporal changes in climate, as well as the distribution of water bodies, habitats and wildlife. Predicting where and when mosquito-borne pathogens are likely to occur is vital to safeguarding against outbreaks of human disease and developing strategic mosquito management programs. The aims of our study were to determine: 1) the spatial and temporal variability in mosquito communities over the late summer and early autumn in a metropolitan region; and, 2) the presence of arboviruses in the various mosquito species at the sites and the implications for mosquito-borne disease risk. Mosquito populations were sampled, and tested for the presence of arboviruses, using a replicated CO2 trap sampling design to determine the spatial and temporal variability in mosquito communities over the late summer and early autumn in the metropolitan region of Sydney, Australia. Eleven sites were classified as highly urban, suburban or estuarine, based on the water habitats present and distance from the central business district. Mosquito community composition within metropolitan urban regions was not significantly different from those in suburban areas with nearby bushland. However, areas associated with estuarine wetlands recorded significantly different mosquito fauna and a higher abundance of mosquitoes. Stratford virus was the only arbovirus detected in the study and was detected at a higher incidence at the three estuarine sites. This mosquito-borne pathogen is considered of only minor public health concern and while more hazardous viruses were not detected, the high abundance of known vector mosquito species highlights the potential risk and suggests the need for annual surveillance to assist local health authorities mange these risks. Our findings highlight the importance of considering estuarine areas separately when assessing the risk of mosquito-borne disease. This is critical for many cities globally, as important population centres are often located in coastal areas adjacent to estuarine wetlands.

Buying environmental problems: The invasive potential of imported freshwater turtles in Argentina

Abstract In recent years, decision‐makers in Argentina have allowed the legal import of thousands of specimens of freshwater turtles. Given their invasive potential, many of the imported species have become established and have spread to other countries. The three most commonly imported species recently have been Graptemys pseudogeographica, Trachemys scripta, and Pseudemys nelsoni, all of them native to North America. This study assessed the invasive potential of these species in Argentina based on (i) bioclimatic envelope models, (ii) distribution of water bodies, (iii) location of the most populated cities, (iv) comparisons between their alien and native climatic niches, and (v) the main ecological traits of those species. The results showed that these species are able to establish viable populations in Argentina, especially T. scripta and G. pseudogeographica. This is because the country offers a large amount of suitable climatic space for these species, in which there are large areas with rivers and other water bodies. The situation is especially problematic in freshwater ecosystems of the north east, as well as in the most populated portion of the country. A range of regulatory policies are suggested, which could help to reduce biodiversity loss and economic impacts in the future.

D2. Screening of preeclampsia (PE) in the first trimester: high total vascular resistance (TVR) with a reduced fat mass increase the risk in normo BMI patients

Introduction: Abnormalities of cardiac output, TVR and water body distribution are connected with PE and foetal growth restriction (FGR).Targets: To identify patients at risk of PE in the first trimester through USCOM system, bioimpedance and combined screening (maternal history, biophysical and biochemical markers). We enrolled 150 healthy nulliparous women with normal BMI.Results: The patients were divided into two groups: Group A (TVR <1200 dynes sec cm−5), Group B (TVR41200 dynes sec cm−5). Lower values of the Cardiac Output (CO), Cardiac index (CI), Inotropy index (INO), Heart rate (HR) and higher values of Flow Time correct (TFC) have been highlighted in the group B (p < 0.01) compared to group A. 8% of study population developed PE or PE + FGR. In this group 75% of the patients presented high TVR values and 50% is at high risk on the basis of combined screening. We found lower Fat Mass in complicated pregnancies with high TVR values compared to uncomplicated pregnancies with high TVR (Table 1).Conclusions: High TVR and lower Fat Mass in the first trimester may be an early marker of PE more than the combined screening. Moreover, lower fat mass increases the positive predictive value of isolated high TVR from 18% to 50% (Figure 1).Figure 1. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) of high Total Vascular Resistence (TVR), Combined first trimester screening (maternal history + mean artery pressure + pulsatility index of uterine artery Doppler + PAPP-A + PlGF) and high TVR + Fat Mass <20%.

P51. Screening for preeclampsia in the first trimester: A reduced fat mass increases the risk in normo BMI patients

Introduction Maternal cardiovascular system adapts to pregnancy thanks to complex physiological mechanisms that involve cardiac output, total vascular resistance (TVR) and water body distribution. Abnormalities of this adaptive mechanism are connected with hypertensive disorders and foetal growth restriction. Moreover, maternal serum PAPP-A is considered a biochemical marker extensively used for the first trimester screening of PE. Objective To identify patients at high risk of developing hypertensive complications of pregnancy during the first trimester through the use of non-invasive methods such as USCOM (Ultrasonic Cardiac Output Monitor), bioimpedance and biochemical marker. Materials and Methods We enrolled 96 healthy normotensive women with normal Body Mass Index during the first trimester of pregnancy (from 11+0 to 13+6weeks of gestation) obtaining all measurements with the USCOM system, Bioimpedance and collecting MoM values of PAPP-A Results Patients were divided into two groups: Group A ( n =54) with TVR n =42) with TVR >1200dynesseccm −5 . 10% ( n =10) of our study population developed pregnancy complications as IUGR and hypertensive disorders. In this group 81% of patients presented high TVR values and 37% PAPP-A p Conclusions High TVR and lower Fat Mass during the first weeks of gestation may be an early marker of cardiovascular maladaptation more than the evaluation of PAPP-A values and blood pressure assessment.

Assessment of total vascular resistance and total body water in normotensive women during the first trimester of pregnancy. A key for the prevention of preeclampsia

Maternal cardiovascular system adapts to pregnancy, thanks to complex physiological mechanisms that involve cardiac output, total vascular resistance and water body distribution. Abnormalities of these adaptive mechanisms are connected with hypertensive disorders. To identify patients at a high risk of developing hypertensive complications of pregnancy during the first trimester of pregnancy, through the use of non-invasive methods such as USCOM (Ultrasonic Cardiac Output Monitor) and Bioimpedance. We enrolled 120 healthy normotensive women during the first trimester of pregnancy obtaining all measurements with the USCOM system and Bioimpedance. 20 patients were excluded for a bad USCOM signal. The remaining patients (n = 100) were retrospectively divided into two groups: Group A (n = 75) TVR<1200 dynes s cm(-5), Group B (n = 25) TVR>1200 dynes s cm(-5). No statistically significant difference was identified in terms of water distribution, Fat Free Mass, Systolic/Diastolic Blood Pressure, Heart Rate, Hematocrit, Flow Time Corrected and Water Balance Index between the two groups. In contrast, higher values of the Cardiac Output, Stroke Volume, Fat Mass and Inotropy Index have been highlighted in the Group A. Moreover, in the Group A we found a better maternal-neonatal outcome and a lower incidence of hypertensive complications. High TVR during the first weeks of gestation may be an early marker of cardiovascular maladaptation more than the evaluation of water distribution and, in particular, with respect to the single blood pressure assessment. Moreover lower values of Inotropy Index could be an indicative of the worst cardiac performance.

A hybrid inverse-modeling technique to estimate circulation in a steady wind driven open channel flow

A pollutant transport model for small water bodies is proposed in this paper. This novel model uses kriging and a simple neural network in combination with limited physics to model transport of pollutants in water body instead of trying to model all natural hydrodynamic processes. This technique helps to keep the unknown parameters in the model to fewer numbers compared to models with similar spatial resolution. As such, the model is suitable for ‘inverse modeling’ and predicting the pollutant distribution in water bodies. The model is validated with extensive simulated data and lab scale experiments.

The historical distribution of main malaria foci in Spain as related to water bodies.

The possible connectivity between the spatial distribution of water bodies suitable for vectors of malaria and endemic malaria foci in Southern Europe is still not well known. Spain was one of the last countries in Western Europe to be declared free of malaria by the World Health Organization (WHO) in 1964. This study combines, by means of a spatial-temporal analysis, the historical data of patients and deceased with the distribution of water bodies where the disease-transmitting mosquitos proliferate. Therefore, data from historical archives with a Geographic Information System (GIS), using the Inverse Distance Weighted (IDW) interpolation method, was analyzed with the aim of identifying regional differences in the distribution of malaria in Spain. The reasons, why the risk of transmission is concentrated in specific regions, are related to worse socioeconomic conditions (Extremadura), the presence of another vector (Anopheles labranchiae) besides A. atroparvus (Levante) or large areas of water bodies in conditions to reproduce theses vectors (La Mancha and Western Andalusia). In the particular case of Western Andalusia, in 1913, the relatively high percentage of 4.73% of the surface, equal to 202362 ha, corresponds to wetlands and other unhealthy water bodies. These wetlands have been reduced as a result of desiccation policies and climate change such as the Little Ice Age and Global Climate Change. The comprehension of the main factors of these wetland changes in the past can help us interpret accurately the future risk of malaria re-emergence in temperate latitudes, since it reveals the crucial role of unhealthy water bodies on the distribution, endemicity and eradication of malaria in southern Europe.

Extraction of water areas based on similarity analysis using pixel-level SAR image time series

In view of the characteristics of SAR images stack data,this paper presents a method for extraction of the water area based on similarity analysis using pixel- level SAR image time series. The basic idea is as follows:Firstly,the pixel- level SAR image time series is constructed,and the dynamic time warping( DTW) is chosen as the similarity measurement to compute the similarities between all the pixels and sampled water pixel. Then,the water pixels are extracted with the threshold value method,referring to the DTW distance of mixed pixels on borders of water for threshold value. Lastly,by replacing the backward scattering coefficients with DTW distance of each pixel,the accuracy of water identification is improved by 8- connected method. 25 wide- swath ENVISAT ASAR images collected during the period from January to December in 2008,which have 150 m spatial resolution,were utilized to extract water pixels in the study area. The result shows that the water pixels extracted by this method have high accuracy and integrity,thus proving that this method is practical in the extraction and mapping of water body distribution at the large regional scale.

Abundance of water bodies is critical to guide mosquito larval control interventions and predict risk of mosquito-borne diseases

Characterization of mosquito breeding habitats is often accomplished with the goal of guiding larval control interventions as well as the goal of identifying areas with higher disease risk. This characterization often relies on statistical measures of association (e.g., regression coefficients) between covariates and presence/absence or abundance of larva. Here we contend that these measures of association are not enough; researchers should also study the spatial and temporal distribution of water bodies. We provide recommendations on how current methodology may be improved to adequately take into account the distribution of water bodies.

The estimation and significance of Dar-Zarrouk parameters in the exploration of quality affecting the Gulf of Aqaba coastal aquifer systems

The subsurface resistivity layer parameters of 47 vertical geoelectrical soundings are analyzed for a rectangle shaped area of 70 km2 from the Gulf of Aqaba coast. For this purpose, the Dar-Zarrouk parameters i.e., (i) total longitudinal unit conductance, (ii) total transverse unit resistance and (iii) average longitudinal resistivity are used to determine the resistivity regime of the water bearing formations. The significance of these parameters is to establish a vision about the occurrence and distribution of water bodies, while dealing with complicated situations of resistivity ranges intermixing for saline, brackish and fresh water aquifers. The results obtained from the study area suggest that the Dar-Zarrouk parameters proved useful in providing confident solution to delineate water-bearing formations. The behavior of the Dar-Zarrouk parameters and its patterns in space over large areas with respect to the occurrence of water aquifer systems in the deltaic coastal area has been demonstrated.

Distribution of fish in the river system of the Lower Irtysh

We report the results of investigation of fish distribution in water bodies of different types (open floodplain complex, closed lake, floodplain channels, and a riverbed depression) of the river system of the Lower Irtysh obtained by application of differently aimed hydroacoustic complexes and by traditional ichthyological methods. Distribution, composition, and abundance of fish aggregations and their diurnal movements are determined in different water areas. Periodicity, range, and direction of fish migrations, rhythm of downstream migrations of juveniles under various conditions are recorded. Distribution of fish is considered as a continual process controlling the biological integrity of the river system. Significant presence of nomadity (various migrations and local movements) is demonstrated in fish, reflecting multilevel lability of the environment in the floodplain-channel system of the Lower Irtysh. A set of notions is suggested defining application limits of principal terms characterizing fish movements of various scales: migrations, wanderings, and short-term movements.

Climate‐driven variability in lake and wetland distribution across the Prairie Pothole Region: From modern observations to long‐term reconstructions with space‐for‐time substitution

This study was designed (1) to explore the links between climate variability and the population dynamics of closed‐basin surface water bodies of the Prairie Pothole Region (PPR) in North America, and (2) to test the validity of space‐for‐time (SFT) substitution approach for the analysis of hydrologic systems. Observational results from 1981 to 2000 show that the climate with respect to annual residual moisture (ε, i.e., precipitation minus potential evaporation or evapotranspiration) of the PPR changed across space (over 0.6 m) and time (over 0.3 m in central North Dakota), causing spatiotemporal variability in water areas and water body numbers. Spatial analysis of a suite of surface water complexes along a spatial ε gradient in the Missouri Coteau shows that a four parameter Boltzmann function quantitatively describes how the number of water bodies (N) varied as a function of 5‐year average annualε (R2 = 0.76). Temporal analysis of monthly N data (1931–2005) reconstructed by a hydrologic model also demonstrates that values of temporally varying N were highly correlated with εand yielded a nearly identical Boltzmann function. This result confirms the validity of SFT substitution and suggests that detailed modern spatial data can be used to interpret hydrologic system behaviors under past or future climate conditions. This study also has important regional‐scale implications for water resources management by providing a complete picture of the spatiotemporal water body distribution across the entire PPR and the potential for rapidly converting climate predictions into surface water assessments.

Spatial correlation between malaria cases and water-bodies in Anopheles sinensis dominated areas of Huang-Huai plain, China.

BackgroundMalaria re-emerged in the Huang-Huai Plain of central China during 2006–2008, dominated with Anopheles sinensis as a vector. However, there is no information on strategies based on multi-factor analysis to effectively control the re-emergence of malaria in these areas. Previous experience indicates some relationship between the distribution of water bodies and malaria cases, but more detailed data are not available and in-depth studies have not been conducted up to now. The objective of this study was to identify the relationship between the distribution of water bodies and presentation of malaria cases using spatial analysis tools in order to provide guidance to help formulate effective strategies for use in controlling the sources of malaria infection, based on the identification of risk areas and population.MethodsThe geographic information of malaria cases and their surrounding water bodies were collected from Suixi, Guoyang, Guzhen, Yingshang, Fengyang and Yongqiao County in Anhui province, Yongcheng and Tongbai County in Henan province. All malaria cases distributed in 113 villages in these 8 counties were collected from the China Information System for Disease Control and Prevention and confirmed by household investigation. Data on GIS and malaria cases were mapped and analyzed with the software of ArcGIS 9.2 to identify the spatial correlation between malaria cases and water bodies. The distance from households with malaria cases to the nearest water bodies was used to calculate the OR value by Chi-square test. The risk area was identified through the comparison of OR values in different distances.Results357 malaria cases and their GPS data as well as surrounding water bodies were collected and analyzed. 74% of malaria cases were located within the extent of 60 m proximity to the water bodies. The risk rate of people living there and presenting with malaria was significantly higher than others (OR = 1.6,95%CI (1.042, 2.463),P < 0.05).ConclusionsThe results revealed that distribution of water bodies is an important factor influencing the occurrence and distribution of malaria cases in the An.sinensis areas, and implies that the scope and population within 60 m around water bodies are at risk and could be a targeted population for case management of malaria.

Integration of Palmer Drought Severity Index and remote sensing data to simulate wetland water surface from 1910 to 2009 in Cottonwood Lake area, North Dakota

Spatiotemporal variations of wetland water in the Prairie Pothole Region are controlled by many factors; two of them are temperature and precipitation that form the basis of the Palmer Drought Severity Index (PDSI). Taking the 196 km 2 Cottonwood Lake area in North Dakota as our pilot study site, we integrated PDSI, Landsat images, and aerial photography records to simulate monthly water surface. First, we developed a new Wetland Water Area Index (WWAI) from PDSI to predict water surface area. Second, we developed a water allocation model to simulate the spatial distribution of water bodies at a resolution of 30 m. Third, we used an additional procedure to model the small wetlands (less than 0.8 ha) that could not be detected by Landsat. Our results showed that i) WWAI was highly correlated with water area with an R 2 of 0.90, resulting in a simple regression prediction of monthly water area to capture the intra- and inter-annual water change from 1910 to 2009; ii) the spatial distribution of water bodies modeled from our approach agreed well with the water locations visually identified from the aerial photography records; and iii) the R 2 between our modeled water bodies (including both large and small wetlands) and those from aerial photography records could be up to 0.83 with a mean average error of 0.64 km 2 within the study area where the modeled wetland water areas ranged from about 2 to 14 km 2. These results indicate that our approach holds great potential to simulate major changes in wetland water surface for ecosystem service; however, our products could capture neither the short-term water change caused by intensive rainstorm events nor the wetland change caused by human activities.