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Continuous monitoring of agricultural lands is imperative for managing water and soil resources in a watershed, due to its impact on ecosystem health and food security. Global Land Cover (GLC) maps can be used as a proxy for local and regional land use maps because of their availability, variety, and ease of use without complex processing. This study investigates the performance of three GLC products including MCD12Q1 LC, CGLS LC, and CCI LC against a reference land use/ land cover map of the year 2015 in the LUB. First, identical classes between the reference map and the GLC maps were determined based on the main land use/ land cover classes of the reference map of 2015 (rangeland, agricultural land, water, built-up areas, and bare land).
Study RegionLake Urmia, Iran.Study focusThere is widespread interest in restoring drying saline lakes. At Iran’s hypersaline Lake Urmia, managers have sought a uniform target lake level of 1274.1 m above sea level to lower salinity below 263 g L−1 and recover Artemia to sufficient densities to support flamingos. We suggest that addressing a broader range of objectives will allow more flexibility for managing the lake. We define eight restoration objectives to lower salinity, sustain Artemia and flamingo populations, separate islands from each other and the mainland, reduce lakebed dust, maintain commercially valuable ions, and improve recreational access from resort beaches. We use 40 years of experimental, field, satellite, and model d
Study RegionLake Urmia, Iran.Study focusThere is widespread interest in restoring drying saline lakes. At Iran’s hypersaline Lake Urmia, managers have sought a uniform target lake level of 1274.1 m above sea level to lower salinity below 263 g L−1 and recover Artemia to sufficient densities to support flamingos. We suggest that addressing a broader range of objectives will allow more flexibility for managing the lake. We define eight restoration objectives to lower salinity, sustain Artemia and flamingo populations, separate islands from each other and the mainland, reduce lakebed dust, maintain commercially valuable ions, and improve recreational access from resort beaches. We use 40 years of experimental, field, satellite, and model d
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Saline lakes are drying worldwide and there is widespread interest to restore them as the costs of lake desiccation can decimate adjoining economies and ecosystems. Here we synthesize 40 years of the available experimental, field, satellite, and model data for Lake Urmia in northwest Iran, which once was one of the world’s largest hypersaline lakes. We use the noisy data to define 10 restoration objectives for dust control, salinity, ionic composition, brine shrimp (Artemia spp.) survival, greater flamingo (Phoenicopterus roseus) abundance, island separation from each other and the mainland, connection between the north and south arms of the lake, recreational access, and agricultural benefits. We relate each objective to lake level and f
More than 5 million people live near Lake Urmia in northwestern Iran. Urmia is one of the world's largest hypersaline lakes, yet over the past two decades, the lake has lost 95% of its volume and the lake level has dropped more than 7 m. We synthesized 40 years of available data, defined 10 management objectives for human health, water quality, ecology, recreation, and agro-economy (Box 1), and described trade-offs between those objectives and lake level. Results show that a single" ecological level" such as that set recently by the Iranian government may not achieve the objectives. Managers should identify a range of lake levels to maintain priority ecosystem benefits.
Reservoirs are the key infrastructure of water resources management. A controlling variable of reservoir operation is evaporation, which in semi‐arid and arid regions may consume a large fraction of reservoir storage annually. This paper assesses the role of evaporation and the choice of evaporation methods on reservoir operation. The operation of the reservoir is calculated with the standard operation policy (SOP). Several efficiency criteria are employed to rank the evaporation‐calculation methods with the technique for the order of preference by similarity to ideal solution (TOPSIS). The method presented in this paper is illustrated by applying its application to Karkheh reservoir, the largest in Iran.
The large decline in Lake Urmia's level since 1995 has prompted a correspondingly large increase in research to help inform lake restoration. Here we synthesize results from 451 English-language articles (Figure 1) to answer four lake restoration questions of interest to the public and lake managers. We ask: 1) What lake restoration levels were considered besides the ecological level of 1274.1 m? 2) How has the causeway affected lake conditions? 3) Do we know enough about lake limnology and ecology to facilitate recovery? And 4) what to learn from Great Salt Lake management? We seek to share these findings with Lake Urmia managers, solicit feedback, and identify next steps for restoration and collaborative work.
Saline lakes play a crucial role in regulating the regional climate, supporting unique biodiversity, and providing a diverse range of economic benefits. However, as a result of growing water withdrawals for human use, most of the large saline lakes worldwide are desiccating at a substantial rate. Water level decline and salinity rise affect physico-chemical characteristics of saline lakes including surface albedo. Water surface albedo impacts lake color and evaporation. Here, we investigate spatio-temporal variation of surface albedo over Lake Urmia, in northwest Iran, using the MODerate Resolution Imaging Spectroradiometer (MODIS) albedo product (MCD43D) from 2000 to 2019. Satellite-derived shortwave albedos were validated against in-situ
Evaporation is one of the principal components of the water balance equation in a basin. For large water bodies located in arid regions, particularly in endorheic basins, evaporation loss is remarkable. Because of the considerable variation of hydro-meteorological variables over large basins, several models have been developed to estimate evapo-transpiration using remote sensing data. However, performance of such models over water bodies are questionable as they neither consider the lake geomorphology nor the water quality. Estimating evaporation from saline lakes is more difficult than that of the fresh water because the interaction of salinity and evaporation should also be considered. This study aims at comparing three energy balance mod
Harmful algal blooms (HABs) can adversely affect coastal activities, marine aquaculture, and economy of the affected waters. The Strait of Hormuz at the east part of the Persian Gulf is highly prone to the HAB because of receiving considerable nutrients either from its coastal regions or from pollutant currents from Oman Sea. Early detection of HABs is of high importance in this strategic region. This study aims at identifying key variables affecting the formation and expansion of HABs in the Strait of Hormuz and its detection using satellite data. Three main events were studied between September 2008 to December 2014, each lasting for more than a month. MODIS satellite data based models of chlorophyll-a (Chl-a) concentration, sea surface t
Satellite time series data play a key role in characterizing land surface change and monitoring of short and long-term land cover change processes over time. While coarse spatial resolution optical sensors (eg MODIS) can provide appropriate time series data, the temporal resolution of high to intermediate spatial resolutions sensors (1-100 m eg Landsat) does not allow for having temporally frequent measurements because of the orbital configuration of such sensors and cloud contamination. A promising approach for addressing this challenge and producing Landsat-like imageries is the blending of data from coarse spatial resolution sensors like MODIS. Among different approaches proposed in the literature, the ESTARFM model has been reported to
Evapotranspiration (ET) is an important water loss component in a catchment-scale water accounting. Because of the difficulties in direct measurement of ET, numerous physically-based models have been developed to estimate evaporation and evapotranspiration. Among them, the energy balance model outperforms others. Remote sensing-based energy balance models such as SEBAL and SEBS are capable of evaluating ET at regional scale without the need for quantifying complicated relevant hydrological process. Although these models originally were developed for agricultural areas, they include empirically adjusted parameters and equations for application over water bodies. A number of studies on basin-scale application of these models over land & water
Large volumes of water evaporate from reservoirs in arid and semi-arid regions. Such water losses are substantial in the regional water balance, and must be considered in the management of water resources. This paper evaluates 12 reservoir evaporation methods that are applied to calculate daily evaporation from Karkheh reservoir (Iran) created by the world’s sixth largest dam. The Bowen ratio energy budget (BREB) formula is chosen as the reference method for the purpose of evaluating 12 alternative evaporation methods. The evaporation methods are ranked based on their accuracy, sensitivity to input variables, and simplicity of application by means of the technique for order of preference by similarity to ideal solution (TOPSIS) multi-crit
This study investigates the Buffer area of Lake Uremia main southern streams including Siminehroud, Gadarchay and Mahabadchay as south western streams, Zarinehroud and Mardoughchay as southern streams and Ghalechay and Soufichay as south eastern streams. Buffer zone area is located between maximum extent and daily extent of Lake Uremia which is selected as the study area. The study is done based on images from 143 days in the year 2010 in which the buffer area and the extent of the southern streams were not cloudy. Using available data from Bonab meteorological station and tail-end hydrometry stations, changes of the Buffer area were analyzed. The aim of this study is to determine the daily variations of the river flood plains in the southe