The development of an historical baseline of water balance and environmental flows

2003 ◽  
Vol 48 (7) ◽  
pp. 139-147 ◽  
Author(s):  
M.P. Papworth ◽  
B. Lewis

This paper has been motivated by a desire to put some numbers beside the label of sustainability as is currently applied to water related issues. Of particular interest is a general estimate of the water balance and environmental flows during the time intervals before Aboriginal arrival, when the land was being managed in an environmentally sustainable manner by the Aboriginals, and most recently following European settlement. This will be considered in an Australia-wide context, because the continent is geographically diverse, being mostly arid desert, with limited areas of fertile soils. Climate variation ranging from a hot tropical north to a cool temperate south will also be discussed. Attention will be given to the major factors that have influenced the water balance, including the extinction of Australian megafauna, the effects of “fire-stick” farming and the clearance of land for European agriculture with its consequences. It is hoped that the findings will increase our understanding of Australian water resources, and promote a greater appreciation of the fragility of this ancient landscape on which we dwell.

Author(s):  
A.C. Johnstone

The aim of the study is to determine if pit lakes are a sustainable coal mine closure option in South African. The water balance, chemistry, limnology, and bacterial population of three selected pit lakes were investigated. The lakes are in the three major coal basins of South Africa and are associated with different lithologies and mining methods. The major factors driving the water balance of the pit lakes are direct rainfall, runoff, inflow from old mine workings, and groundwater infiltration, with the major losses being evaporation or discharge onto surface. The study indicated that pit lakes can be designed as 'terminal sinks' to provide a sustainable mine closure option. The pit lakes sampled have an alkaline pH, and mostly a sodium/calcium sulphate water with total dissolved solids content of less than 3000 mg/l. The phytoplankton and microbiological data indicates that the pit lakes support aquatic life. The study shows that correctly designed pit lakes can be an environmentally sustainable closure option for South Africa's coal mines. A suggested design manual has been developed to assist mine owners and regulators in developing sustainable coal mine pit lakes as a closure option.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. K. Jaiswal ◽  
Sohrat Ali ◽  
Birendra Bharti

AbstractThe design of water resource structures needs long-term runoff data which is always a problem in developing countries due to the involvement of huge cost of operation and maintenance of gauge discharge sites. Hydrological modelling provides a solution to this problem by developing relationship between different hydrological processes. In the past, several models have been propagated to model runoff using simple empirical relationships between rainfall and runoff to complex physical model using spatially distributed information and time series data of climatic variables. In the present study, an attempt has been made to compare two conceptual models including TANK and Australian water balance model (AWBM) and a physically distributed but lumped on HRUs scale SWAT model for Tandula basin of Chhattisgarh (India). The daily data of reservoirs levels, evaporation, seepage and releases were used in a water balance model to compute runoff from the catchment for the period of 24 years from 1991 to 2014. The rainfall runoff library (RRL) tool was used to set up TANK model and AWBM using auto and genetic algorithm, respectively, and SWAT model with SWATCUP application using sequential uncertainty fitting as optimization techniques. Several tests for goodness of fit have been applied to compare the performance of conceptual and semi-distributed physical models. The analysis suggested that TANK model of RRL performed most appropriately among all the models applied in the analysis; however, SWAT model having spatial and climatic data can be used for impact assessment of change due to climate and land use in the basin.


1995 ◽  
Vol 44 (2) ◽  
pp. 181-189 ◽  
Author(s):  
John Lichter

AbstractA sequence of northern Lake Michigan beach ridges records lake-level fluctuations that are probably related to changes in late Holocene climate. Historically, episodes of falling and low lake level associated with regional drought led to the formation of dune-capped beach ridges. The timing of prehistoric ridge formation, estimated by radiocarbon dating of plant macrofossils from early-successional dune species, shows that return periods of inferred drought, averaged for time intervals of 100 to 480 yr, ranged between 17 and 135 yr per drought during the last 2400 yr. In five of ten of these time intervals, the average return period ranged between 17 and 22 yr per drought. These intervals of frequent ridge formation and drought were associated with the development of parabolic dunes, which is indicative of high lake level and moist climate. This seeming paradox suggests that unusually moist decades alternated with unusually dry decades during these time intervals. Regional water balance probably varied less during the time intervals when ridges formed less often and the lake produced no evidence of high level.


2008 ◽  
Vol 3 (2) ◽  
Author(s):  
J.M. Anderson

Climate change due to global warming will reduce river flows across much of Australia and reduce the yield of existing urban and rural water systems. These reductions are additional to yield reductions that have flowed from the allocation of more water for environmental flows under national water reforms, and the severity of the 2001-2007 drought in southern Australia. Australian water authorities are adapting to these changes by implementing extensive water savings programs and by developing new water sources including water reuse, stormwater and desalination as well as traditional river and groundwater sources. The paper describes two case studies and discusses how stochastic analysis of system scenarios can help identify drought and climate change risks and the economic benefits of water reuse.


2014 ◽  
Vol 14 (3) ◽  
pp. 5-14
Author(s):  
Ryszard Błażejewski ◽  
Sadżide Murat-Błażejewska ◽  
Martyna Jędrkowiak

Abstract The paper presents a water balance of a flow-through, dammed lake, consisted of the following terms: surface inflow, underground inflow/outflow based on the Dupuit’s equation, precipitation on the lake surface, evaporation from water surface and outflow from the lake at which a damming weir is located. The balance equation was implemented Matlab-Simulink®. Applicability of the model was assessed on the example of the Sławianowskie Lake of surface area 276 ha and mean depth - 6.6 m, Water balances, performed for month time intervals in the hydrological year 2009, showed good agreement for the first three months only. It is concluded that the balancing time interval should be shorter (1 day) to minimize the errors. For calibration purposes, measurements of ground water levels in the vicinity of the lake are also recommended.


Author(s):  
Eugênio Ferreira Coelho ◽  
Marcos de Souza Campos ◽  
Marcelo Rocha dos Santos ◽  
Rafael Dreux Miranda Fernandes ◽  
Jailson Lopes Cruz

Precise, accurate knowledge of percolation is key to reliable determination of soil water balance and a crop’s water-use efficiency. This work evaluated an approach to estimate the amount of water percolated in the root zone using soil water content (SWC) data measured at different time intervals. The approach was based on the difference of soil water content within and below the effective root zone of banana plants at different time intervals. A drainage lysimeter was used to compare the measured and estimated percolation data. The approach was then used in a banana orchard under drip and micro sprinkler irrigation, with and without the use of mulch. The soil water storage in the banana’s root zone was evaluated within a two-dimensional soil profile with time domain reflectometry (TDR). Mean percolation measured in the lysimeters did not differ from the approach’s estimates using intervals between SWC readings equal to or longer than 6 h from the end of an irrigation event. Percolation estimates under drip and micro sprinkler irrigation in the field, with and without mulch, were consistent with those measured in the lysimeters, considering the 6-h interval of SWC measurements. Percolation was greater under the drip irrigation system with mulch. The amount of water percolated was not influenced by the presence of mulch under the micro sprinkler system. Keywords: localized irrigation, soil water balance, soil water content sensor.


2021 ◽  
Vol 25 (8) ◽  
pp. 4567-4584
Author(s):  
Siyuan Tian ◽  
Luigi J. Renzullo ◽  
Robert C. Pipunic ◽  
Julien Lerat ◽  
Wendy Sharples ◽  
...  

Abstract. A simple and effective two-step data assimilation framework was developed to improve soil moisture representation in an operational large-scale water balance model. The first step is a Kalman-filter-type sequential state updating process that exploits temporal covariance statistics between modelled and satellite-derived soil moisture to produce analysed estimates. The second step is to use analysed surface moisture estimates to impart mass conservation constraints (mass redistribution) on related states and fluxes of the model using tangent linear modelling theory in a post-analysis adjustment after the state updating at each time step. In this study, we assimilate satellite soil moisture retrievals from both Soil Moisture Active Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) missions simultaneously into the Australian Water Resources Assessment Landscape model (AWRA-L) using the proposed framework and evaluate its impact on the model's accuracy against in situ observations across water balance components. We show that the correlation between simulated surface soil moisture and in situ observation increases from 0.54 (open loop) to 0.77 (data assimilation). Furthermore, indirect verification of root-zone soil moisture using remotely sensed Enhanced Vegetation Index (EVI) time series across cropland areas results in significant improvements from 0.52 to 0.64 in correlation. The improvements gained from data assimilation can persist for more than 1 week in surface soil moisture estimates and 1 month in root-zone soil moisture estimates, thus demonstrating the efficacy of this data assimilation framework.


2020 ◽  
Vol 12 (15) ◽  
pp. 2452
Author(s):  
Yu-Jun Ma ◽  
Fang-Zhong Shi ◽  
Xia Hu ◽  
Xiao-Yan Li

The sustainability of dryland vegetation growth over the Silk Road Economic Belt is under threat of water shortage, and the determination of water carrying capacity for vegetation is critically essential to balance water supply and water demand for the maintenance of existing ecosystems. To better understand how and why vegetation growth varies in different desert areas, this study first analyzed the spatiotemporal variation of the normalized difference vegetation index (NDVI). Then, we investigated the relationship between NDVI and climatic factors (precipitation, soil water content, air temperature, evapotranspiration), and estimated the threshold NDVI under water balance in different desert areas. Results showed that the higher NDVI was mainly distributed in Kazakhstan, Russia, and Azerbaijan, and it increased in approximately 53% of desert areas from 1982 to 2015 in the whole study region. The mean annual NDVI showed a simultaneous increasing trend in all desert areas from 1982 to 1994, and decreased significantly only in the cold arid desert area (p < 0.01, −0.0067 decade−1) or had no significant change in other desert areas after 1994 (p > 0.01). The climate condition generally appeared as a warming and drying trend in the past 34 years, with varied changing rates in different desert areas. NDVI presented a strong positive relationship with both precipitation and evapotranspiration in most desert areas. The threshold values of the mean annual NDVI under water balance between 1982 and 2015 were approximately 0.1041 (hot arid desert), 0.1337 (cold arid desert), 0.1346 (cold arid semi-desert), 0.0951 (hot arid desert semi-desert), 0.0776 (polar desert tundra), 0.1071 (hot arid desert shrub), 0.1377 (cold arid desert steppe), and 0.0701 (polar desert steppe), respectively. The responses of these threshold values to precipitation were all positive in different desert areas. These results provide an enhanced understanding of vegetation dynamics and ecological conservation, which are of great importance to implementing adaptation and mitigation measures for terrestrial ecosystems over the Silk Road Economic Belt.


2020 ◽  
Vol 32 (4) ◽  
pp. 157-165
Author(s):  
Alekseitseva V. ◽  
◽  
Shnaider S. ◽  
Rudaya N. ◽  
Saifuloev N. ◽  
...  

This article is devoted to a review of the data on the chronology of the occupation of the Eastern Pamirs high-lands and the paleoecological reconstructions. At this moment it is known that there are two main episodes of the settlement of the region in the Final Pleistocene – Middle Holocene: 12–8 ka BP. (the main archaeological sites are the Istyk cave and the Kurteke grotto) and 8–6 thousand years ago (Oshkhona, Shakhty, Istykskaya cave, Kurteke). The review shows that these episodes coincide with the periods of the most favorable paleoclimatic conditions. The climate of the region in general is characterized as arid desert, with a predominance of open spaces of desert-steppe and desert appearance. The time intervals about 15–13 thousand years ago and about 9–8 thousand years ago are characterized with a transition from xerophilic groups to more mesophilic, which indicates a humidification of the climate during these periods. The researchers note that these climatic changes are likely to be pan-regional. The revealed cyclicality of climate changes in the Eastern Pamir region is comparable to archaeological data: the time intervals in when an increase in the climate humidity of the region is noted are similar to the intervals in when, according to archaeological data, the region was populated. Further paleoecological reconstructions of the Eastern Pamirs will reveal the connection between the cyclicality of climatic changes in the region and human settlement in its territory.


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