Basin Flooding Research Articles

Dam failure analysis according to different methods in HEC-RAS, Gökçe Dam, Turkey

As in the rest of the world, the impact of climate change is clearly felt in Turkey, while the effects of global warming, drought and flood-induced disasters continue to increase day by day. At the same time, water consumption is crucial for the survival of people. Efficient water use and conservation, facilitated by water resources management, should be recognized as a pressing contemporary concern. Recently, floods that cause a great deal of damage have started to occur frequently in Turkey. A possible flood that may occur in the demolition of Gökçe Dam has been a matter of curiosity. This dam is the most important water source for Yalova province and has been in service for a long time. Therefore, the aim of this study is to examine the flood risk situations of settlements in case of a possible Gökçe Dam failure or basin flooding. Additionally, the study aims to estimate the damages that may occur in houses of flooded areas. Piping and overtopping methods were used in HEC-RAS program to create flood maps, and the Van Eck and Kok damage curves were used to assess the damages. While water level varies between 0-1 meters in the most affected buildings in the overtopping method, this level is 2-3 meters in the piping method. The damage to buildings with a water level of 4 meters and above is quite high in the piping method, and it has been observed that greater damage may occur for lower water levels in the overtopping method. The total damage and number of affected buildings are higher in the piping method. Accordingly, a possible Gökçe dam failure would cause significant losses in both methods, especially in the piping method.

Effect of the Entire Coal Basin Flooding on the Land Surface Deformation

Effect of the Entire Coal Basin Flooding on the Land Surface Deformation

The Trends and Effects of Flood Occurrences in the Shire River Basin in Chikwawa District of Malawi: A Historical Perspective (1980 - 2019)

Purpose: The purpose of this study was to examine historical trends in flooding in Malawi’s Shire River Basin (SRB). The basin is prone to severe flooding and most affected in the country. For many years, flooding has posed a significant threat to communities in and around the basin. Therefore, the main objective of the study was to document the historical perspective of flood occurrences in terms of frequency and impact in the Shire River Basin of Chikwawa District, Malawi, from 1980 to 2019. 
 Methodology: A mixed survey design was used for the study. Both random and purposive sampling were used to identify participants. A total of 384 respondents took part in the study. The study collected both primary and secondary data. Primary sources of data were collected using household surveys, interviews with key informants, and focus group discussions, while secondary sources of data were collected using documents from both non-governmental and Malawian governmental departments and agencies (MDAs) as well as existing literature. Data from focus group discussions (FGDs), interviews with community elders (CEIs), and key informant interviews (KIIs) were recorded in Chichewa with a voice recorder, transcribed in Chichewa, and then translated into English. Household survey data were processed using Statistical Package for Social Scientists (SPSS) version 25 and secondary data were converted to time series data and then analysed using STATA software to produce charts and graphs. 
 Findings: The results showed that all three hydrometeorological extremes (mean annual temperature, average rainfall and baseflow index) increased, suggesting that both the intensity and frequency of flooding in the Shire River Basin of Chikwawa District were also increasing in absolute terms. People’s perceptions of flooding showed that the Shire River Basin in Chikwawa District experienced excessive flooding every 5 years. This 5-year cycle was, among other factors the result of climate change and forest loss in the study area, leading to an increase in river sedimentation.
 Recommendations: This article found that the local people in the Shire River Basin of Chikwawa District will always live with increasing levels of flooding. Therefore, they should be proactive in flood management and understand the process as an ongoing activity for future risk assessment. Analysing the history of river basin flooding is important as it helps the Malawi's Department of Disaster Management Affairs (DoDMA) officials to be alert and estimate the time frame for the next flood in the Shire River Basin of Chikwawa District to strengthen the flood forecasting accuracy.

Impacts of a shallow saline water table on maize evapotranspiration and groundwater contribution using static water table lysimeters and the dual Kc water balance model SIMDualKc

The occurrence of shallow saline water tables in arid zones provides for groundwater-fed natural vegetation and for a substantial amount of irrigated crops’ water needs. This is the case of the Hetao plain, upper Yellow River Basin, Inner Mongolia, China, where one of the major irrigation systems of China and the World is installed. As reviewed, numerous irrigation and water management studies have been developed in Hetao and the upstream irrigated plain of Yinchuan, Ningxia. These studies have demonstrated the need for controlling salts through the autumn irrigation and the appropriate irrigation methods and scheduling. Moreover, studies evidenced the need for adopting irrigation schedules that consider groundwater contribution during the crop cycle but most of these studies were empirical, resulting difficult to transfer results. When models adopted were mechanistic, they are difficult to use for irrigation scheduling purposes comparatively with soil water balance (SWB) models. Thus, the current study used two sets of five static water table lysimeters cropped with maize and having water table depths (WTD) fixed between 0.85 and 2.25 m. It was therefore possible to observe the daily capillary rise fluxes from the water table, the dynamics of water and salts and to calibrate the SWB model SIMDualKc. Results show that the average electrical conductivity of the saturated extract of the soil ranged from 3.10 to 4.69 dS m−1 with the higher values observed when WTD was smaller, while the electrical conductivity of irrigation water ranged 1.73–1.87 dS m−1. Results also show that shallower WTD required less irrigation water but caused higher salinity impacts on crop growth and yields. Thus, the best WTD were around 1.75–2.00 m when basin irrigation was adopted in 2017 and 2018. In these crop seasons, the simulated groundwater contribution to actual crop evapotranspiration (ETc act) was up to 37% in the lysimeters having a shallow WTD (1.25 m), while in the lysimeters with deeper WTD (2.00–2.25 m) it was about 11% of the ETc act. Contrastingly, in 2019, when maize was not irrigated, the average groundwater contribution represented 73% and 49% of ETc act in the lysimeters with shallow and deep WTD, respectively. Results were obtained when a large leaching autumn irrigation (200 mm) was performed. Those experiments showed that, solutions for using basin flooding irrigation are ready but still require that irrigation scheduling is adjusted to provide for appropriate use of the saline groundwater contribution, which may be performed with the model SIMDualKc, as demonstrated by the high goodness-of-fit indicators used to evaluate the referred simulations.

Export and risk from antibiotic remobilization from surrounding water to lake in the extreme 2020 Yangtze River basin flooding

Global climate change increased the frequency of extreme rainfall events, leading to higher flood risk. In addition to the personal and property losses, another important consequence of a flood disaster was release and exposure risks from emerging contaminants, which was usually overlooked. The remobilization and fate of the antibiotics induced by floods remain unclear. We captured antibiotic concentrations around the Chaohu Lake after an unprecedented flood with a range of 5.0–317 ng/L. Higher concentrations in polder waters than their receiving rivers were attributed to the antibiotic release from soil particles and the sharp increase of water: soil ratio by flood storage. Source apportionment analysis of antibiotics implied that diffuse pollution by manure application and aquaculture activity was the predominant sources. Commonalities of spatial variations of antibiotics in polders were related to the condition of waterlogging and pollution source. The total antibiotic storage for all submerged polders was estimated at 27.9 kg. The concentrations and risks from pumping floodwater detained by polders into the lake were much higher than that from discharging flood directly into the lake. The retention-reaction-remobilization process would pose unexpectedly high risks for the lake. This study provided a new sight for constructing ecological wetland flood storage areas.

Modeling of the Geological Probability Procedure for the Prediction of High Flows in Small Streams, Case Study of Medvednica Mt., Croatia

Floods are defined by maximum water levels or flow of high-water waves. Here, we defined the deterministic method for the calculation of the probability of a high discharge event, named as the Probability Of Success (POS). The POS method previously developed for petroleum subsurface systems has been modified for the surface hydrological system with the purpose of flood prediction. The case study of this research is the small basin of Kašina Stream on Medvednica Mt. (NW Croatia). The data are obtained upstream from the hydrological station Gornja Kašina. The POS model is defined by four categories. Each geological category is described with accompanied events and probabilities. Floods are defined by four categories: total precipitation, total water flow, basement, and maximal water capacity in soil. The categories total precipitation and basement were divided into two sub-categories each: quantity and duration; porosity and soil depth. Data are collected for a hydrometeorological event, namely an intensive convective storm on 24–25 July 2020, when Zagreb was locally hit by heavy urban floods. The presented probability method yielded a probability of 1.76% that such an event could happen to the station. However, the flooding was not recorded. A comparison of the real event and the predicted probability supported the adequacy and applicability of the method, showing it has high reliability. The presented probability model could be easily applied, with small modifications, to the entire area of Northern Croatia for the prediction of small basin flooding events.

Reflections on the Catastrophic 2020 Yangtze River Basin Flooding in Southern China

Reflections on the Catastrophic 2020 Yangtze River Basin Flooding in Southern China

Calculation of total phosphorus loads from rivers around Lake Taihu and analysis of total phosphorus fluctuation in the lake in 2015-2016

太湖流域水环境综合治理力度空前，太湖总磷浓度却于2015、2016年重回升势，蓝藻大面积暴发情况也未得到有效遏制.本文从2015和2016年环太湖河道的进出太湖水量、总磷负荷量计算入手，结合雨情、水情、太湖调蓄以及人为影响等各方面因素，分别开展水量和总磷负荷质量的平衡分析.在此基础上，结合2010-2017年环太湖河流多年平均进出太湖总磷负荷量对比，分析太湖总磷的外源、内源变化趋势及来源，探讨2015和2016年太湖总磷升高的原因及控制重点方向.结果表明，2015和2016年为太湖流域丰水年，尤其是2016年发生特大洪水，太湖年内最高水位达4.87 m，仅次于1999年的4.97 m的历史最高水位.2015和2016年大量外源总磷负荷进入太湖，其中环太湖河道带入的总磷负荷量占年度太湖总磷负荷总量的66.8%和74.2%，成为进入太湖的总磷负荷的主要外源；加之，2015年太湖水生植物收割造成当年沉水植物面积较上年同期下降88.7%，水生植物骤减导致对磷的吸收转化能力下降，滞留在湖体中的总磷负荷量占年度太湖总磷负荷总量的21.5%和27.5%，成为影响太湖水体总磷浓度的重要内源.太湖总磷浓度升高又为太湖蓝藻暴发进一步提供了营养盐基础，亟需强化太湖总磷源头的控制、减少总磷入湖总量.;Government has strengthened the comprehensive management and restoration of the water environment in Taihu Basin. Despite the great efforts, the total phosphorus concentration in Lake Taihu rebounded in 2015-2016. Occurrence of cyanobacterial blooms has not been effectively inhibited. Thus, this essay is going to examine the reasons behind and figure out the key direction in controlling the total phosphorus in Lake Taihu. The water quantity balance analysis and the total phosphorus mass balance analysis will be carried out through the calculation of the total phosphorous fluxes and the water flows between Lake Taihu and the surrounding rivers. Affecting factors, including rainfall, lake storage regulation and human factors, will also be considered. Based on the analysis, we will investigate the sources of total phosphorus change in Lake Taihu as well as the reasons of variations. The results showed that Taihu Basin had abundant rainfall in 2015-2016, especially in 2016, there was a severe basin flooding. The maximum water level of Lake Taihu reached 4.87 m, only 0.1 m lower than that of the historical record in 1999. Enormous total phosphorus load flowed from the surrounding rivers to Lake Taihu, which became the main external source of Lake Taihu's total phosphorus load. The load from rivers occupied 66.8% and 74.2% of the annual total phosphorus load in Lake Taihu in 2015 and 2016, respectively. On the other hand, for internal source, the massive reduction of submerged plants played an important role in affecting the total phosphorus concentration in Lake Taihu. The area of submerged aquatic plants in Lake Taihu decreased by 88.7% in 2015. The large-scale harvest of aquatic plants hindered the phosphorus absorption and transformation capacity of the lake. In 2015 and 2016, the total phosphorus load retained in Lake Taihu accounted for 21.5% and 27.5% of the total phosphorus load. The increase in total phosphorus concentration in Lake Taihu provided a strong foundation for cyanobacterial blooms. It is urgent to lower the amount of total phosphorus into Lake Taihu and tighten the control of the total phosphorus sources.

Control of world Albedo by massive salt leaching using the ancient purpose engineered Qanat-Kariz-Falaj technology to control fractional coverage of crystalline white salt precipitation over vast areas of existing endorheic basins.

Huge desert endorheic basins with very substantial areas of flat evaporation pans were once in operation specifically for the precipitation of white crystalline sodium chloride. Maintaining a thin white crust layer of salt during critical hot seasons of the year over these huge areas would increase the world albedo to enable precise control of the total short/long wave reflection, in addition to the high albedo of the polar regions. The surface crust of an inland Sabkha basin typically is made up of layers of salts that have re-crystallized and settled or precipitated during the evaporation process of controlled Qanat system flood waters. Leached Salts dissolve quickly in a desert endorheic basin, and over a short intensely hot period, the process of re-crystallizing the salts can produce purer and more concentrated, layered playa cakes. The dissolved salts leached out of the underlying layers in the vast desert basin flats, are intermittently precipitated back on to the basin surface, predominantly sodium chloride crystals, one after the other leaving the familiar brilliant white salar playa. The original ancient engineered design of the Qanat and its multiple aligned bore-holes was to control desert endorheic basin flooding without destroying the salt mirror playa or causing erosion of the flat evaporation fields. The Qanat was primarily needed to extract salt, rather than for simple irrigation. Additionally considerable quantities of subsoil brines existing in such basin water tables would ensure brine supplies, as is demonstrated by the new potash plants in the Tarim basin using the ancient Qanat technology. The grain size of white sodium chloride crystals may be controlled in a similar way to the fine Polar snow crystals which also provide an improved albedo index. By adding 2-Naphtol green accelerator to the brine, the accepted procedure in the salt industry, analternative switch could reduce the albedo and thus increase warming instead of cooling.

Eficiencia en el uso del agua de variedades de alfalfa (Medicago sativa L.) con sistema de riego subsuperficial

Se realizó un estudio con el objetivo de evaluar la eficiencia del agua de riego en la producción de materia seca y proteína cruda en cinco variedades de alfalfa y dos sistemas de riego, en Zacatecas. La siembra se realizó el 2 de febrero del 2012 bajo un diseño de bloques completamente al azar con arreglo de parcelas divididas y tres repeticiones. Los sistemas de riego evaluados fueron goteo sub-superficial (RGS) e inundación en melgas; y las variedades Silverado, Júpiter, 58n57, Excelente, y Gigante. El análisis estadístico fue en un diseño de parcelas divididas mediante el paquete estadístico SAS. La producción de materia seca (PMS) no se afectó por el sistema de riego (P>0.05), con una media para el total de cinco cortes de 15,561 y 14,121 kg ha-1 para los sistemas RGS e inundación; respectivamente. En cuanto a variedades solamente se encontraron diferencias (P<0.05) en el tercer corte para PMS, sobresaliendo Gigante y Júpiter con 4,638 y 4,263 kg ha-1; respectivamente. No hubo interacción entre riego*variedad (P>0.05). Los sistemas de riego no afectaron el porcentaje de proteína cruda y la producción de proteína cruda del forraje. El sistema RGS redujo en 44 % el volumen de agua aplicada en comparación al riego por inundación. Además en el mismo sentido incrementó la eficiencia del agua de riego en la producción de materia seca y proteína cruda del forraje en 49.2 y 50.9 % respectivamente.

Facies, rock attributes, stratigraphy, and depositional environments: Yanchang Formation, Central Ordos Basin, China

The Late Triassic Yanchang Formation (Fm) is a major target of drilling for hydrocarbons in the Ordos Basin. Although most of the early focus on this thick succession of lacustrine rocks has been the dominant deltaic sandstones and siltstones, which act as local reservoirs of oil and gas, more recent consideration has been given to the organic-rich mudstone source rocks. We used modern chemostratigraphic analysis to define vertical facies successions in two closely spaced cores through the Chang 7 Member, the primary source rock for the Yanchang hydrocarbon system. We used integrated high-resolution X-ray fluorescence and X-ray diffraction measurements to define four dominant facies. Variations in stable carbon isotopes mimic facies stacking patterns, suggesting that terrigenous organic matter (although minor in volume) is associated with the arkoses and sandstones, whereas aquatic organic matter is dominant in the mudstones. Facies stacking patterns define three major depositional cycles and parts of two others, each defined by basal mudstone facies that document basin flooding and deepening (i.e., flooding surfaces). Unconfined compressive strength measurements correlate with clay mineral abundance and organic matter. Comparisons of core attributes with wireline logs indicate that although general variations in clay mineral volumes (i.e., mudstone abundance) can be discerned from gamma-ray logs, organic-matter distribution is best defined with density or resistivity logs. These findings, especially those established between the core and log data, provide a powerful linkage between larger scale facies patterns and smaller scale studies of key reservoir attributes, such as pore systems, mineralogy, diagenesis, rock mechanics, hydrocarbon saturation, porosity and permeability, and flow parameters. This first application of modern chemostratigraphic techniques to the Yanchang Fm reveals the great promise of applying these methods to better understand the complex facies patterns that define this lacustrine basin and the variations in key reservoir properties that each facies displays.

Wild Turkey Movements During Flooding After Opening of the Morganza Spillway, Louisiana

Abstract The opening of the Morganza Spillway in Louisiana on 18 May 2011 to relieve historic flooding along the lower Mississippi river subsequently inundated thousands of acres of bottomland forest in the Atchafalaya basin. Since 2001, we have conducted Meleagris gallopavo silvestris (Eastern Wild Turkey) population ecology research on the Sherburne Wildlife Management Area, located approximately 30 km south of the Morganza spillway. In expectation of the Morganza spillway opening, between 11 and 14 May, we captured and fitted 5 (1 M, 4 F) adult Eastern Wild Turkeys with µGPS transmitters to monitor turkey response to basin flooding. By 19 May 2011, our study area was inundated with >3 m of flood waters, and remained completely inundated until 11 June 2011. Via radio-telemetry, we confirmed one female was depredated immediately before flood waters inundated our study site, and one female survived and reached dry ground created by receding water on 16 June. A second female lived 21 days and made circuito...

Cyclic biogeochemical processes and nitrogen fate beneath a subtropical stormwater infiltration basin

A stormwater infiltration basin in north–central Florida, USA, was monitored from 2007 through 2008 to identify subsurface biogeochemical processes, with emphasis on N cycling, under the highly variable hydrologic conditions common in humid, subtropical climates. Cyclic variations in biogeochemical processes generally coincided with wet and dry hydrologic conditions. Oxidizing conditions in the subsurface persisted for about one month or less at the beginning of wet periods with dissolved O2 and NO3− showing similar temporal patterns. Reducing conditions in the subsurface evolved during prolonged flooding of the basin. At about the same time O2 and NO3− reduction concluded, Mn, Fe and SO42− reduction began, with the onset of methanogenesis one month later. Reducing conditions persisted up to six months, continuing into subsequent dry periods until the next major oxidizing infiltration event. Evidence of denitrification in shallow groundwater at the site is supported by median NO3−–N less than 0.016mgL−1, excess N2 up to 3mgL−1 progressively enriched in δ15N during prolonged basin flooding, and isotopically heavy δ15N and δ18O of NO3− (up to 25‰ and 15‰, respectively). Isotopic enrichment of newly infiltrated stormwater suggests denitrification was partially completed within two days. Soil and water chemistry data suggest that a biogeochemically active zone exists in the upper 1.4m of soil, where organic carbon was the likely electron donor supplied by organic matter in soil solids or dissolved in infiltrating stormwater. The cyclic nature of reducing conditions effectively controlled the N cycle, switching N fate beneath the basin from NO3− leaching to reduction in the shallow saturated zone. Results can inform design of functionalized soil amendments that could replace the native soil in a stormwater infiltration basin and mitigate potential NO3− leaching to groundwater by replicating the biogeochemical conditions under the observed basin.

An Ediacaran iron formation: New evidence for ferruginous late Neoproterozoic seawater

It is widely believed that the Earth's oceans became increasingly oxygenated during the late Neoproterozoic, most notably after the end of the Marinoan glaciation approximately ∼635 million years ago. However, recent geochemical analyses from various Ediacaran sediments suggest that some deep ocean basins were instead anoxic and ferruginous [Fe(II)-enriched] throughout the Ediacaran and possibly into the Cambrian, suggesting a more complex global redox structure than previously thought. Acceptance of this idea has been hindered by an apparent absence of Ediacaran iron formations (IF); chemical sediments that were common under such Fe-rich conditions in earlier Archaean-Palaeoproterozoic oceans. Here, we report detailed sedimentological, stratigraphic, petrographic and geochemical data from an Ediacaran IF and associated rocks, including ‘iron-rich’ black shales, siltstones and chert deposits of the Arroyo del Soldado Group in Uruguay. The Arroyo del Soldado Group is a mixed siliciclastic-carbonate succession interrupted by two major episodes of basin flooding and sediment starvation characterized by the deposition of IF and cherts. On the basis of stacking patterns, two stratigraphic sequences are identified within the group. Sequence A consists of continental shelf siliciclastic facies (Yerbal Formation) grading upward into a carbonate ramp system (Polanco Limestone Formation). Separated by a major erosional unconformity, sequence B is composed of coarse-grained alluvial conglomerates and sandstones (Barriga Negra Formation) capped by finer marine siliciclastics (Cerro Espeulitas Formation). The Yerbal and the Cerro Espuelitas formations, which constitute the main subject of this study, are characterized by retrogradational stacking patterns with fining-upward units deposited during transgressive system tracts. Significantly, the top of both units are characterized by distinct fine-grained siliciclastics and chemical sediments, consisting of banded siltstones, cherts and IF for the Yerbal Formation, and ‘iron-rich’ shales interbedded with black shales that pass upwards into thick chert deposits for the Cerro Espuelitas Formation. Significantly, the Yerbal Formation is a pre-Gaskiers glaciation deposit (ca. 600–590 Ma), while the Cerro Espuelitas Formation is post-Gaskiers (ca. 570–560 Ma) in age, providing insight into the palaeoceanographic conditions immediately before and after the last major Precambrian glacial event. The IF and cherts have coherent rare earth element and yttrium (REY) patterns and display the essential shale-normalized characteristics of marine precipitates. Rare earth element and yttrium signatures and mixing calculations show that they differ from Archaean and Palaeoproteorzoic IF in that high-temperature hydrothermal input did not influence their chemistry. Instead, we suggest that low-temperature hydrothermal input may account for the geochemical signatures displayed. By analyzing the REY signature of chemical precipitates (cherts and IF) and evaluating the redox chemistry of the marine water column within a sedimentological and sequence stratigraphic framework, our results confirm that ferruginous conditions dominated the pre-Gaskiers but also the post-glaciation deep-water chemistry, and that global ocean oxygenation may not have occurred well into the upper Ediacaran or even during the Cambrian, as recently proposed by Canfield et al. (2008).

Stochastic enforced hill-climbing

Enforced hill-climbing is an effective deterministic hill-climbing technique that deals with local optima using breadth-first search (a process called basin flooding). We propose and evaluate a s...

Recognising the Taghanic Crisis in the Devonian terrestrial environment and its implications for understanding land–sea interactions

The late Mid Devonian Eday Marl Formation from the Orcadian Basin, Scotland is a terrestrial equivalent of the marine Devonian Taghanic Crisis. The Eday Marl from Orkney contains a high-resolution archive of climatic change controlled by the relative strength of the seasonal insolation. This includes several distinct and discrete episodes of basin flooding as demonstrated by the deposition of lacustrine laminites, bedded evaporites, marginal sheet flood sands and marine influenced bioturbated sheet sands. These flooding events are intercalated with intense and sustained episodes of aridity indicating that insolation was relatively weak and the monsoon climate was ineffective at drawing in seasonal rainfall. Recognition of these basin flooding events has enabled the definition of three new units (the Wha Taing, Roeberry and Berstane members). The Eday Marl Formation can be correlated offshore and also recognised within marginal facies as an aeolian intercalation. An environmental, hydrological and climatic interpretation is given for the different events recognised in the Eday Marl. This sequence of events, when combined with the palynological age dates, enables a detailed correlation to be made with the marine Tully Formation of New York State. This suggests that regressions forced by climatic aridity are significant for understanding the deposition of the shallow water carbonates of the Tully Formation, in what is otherwise, a clastic depositional system. Comparison with the pelagic marine record shows that the latter, as yet, gives only limited resolution of the Taghanic Crisis. Recognising the Taghanic as a rapid alternation of cool arid and relatively hotter pluvial events provides a unifying explanation for the associated collapse in the terrestrial vegetation and the parallel faunal changes in the marine realm.

Early Paleoproterozoic supracrustal assemblages of the Rae domain, Nunavut, Canada: Intracratonic basin development during supercontinent break-up and assembly

The basal Paleoproterozoic supracrustal succession of the Churchill Province in northern Canada comprises sedimentary basins overlying the Archean Rae and Hearne domains. The Rae domain supracrustal succession (e.g. Amer, Ketyet River, Chantrey and Montresor groups) comprises four lithotectonic assemblages which include, in ascending stratigraphic position: (1) shallow marine-fluvial quartzarenite with mainly Neoarchean detrital zircons of local provenance; (2) shallow marine quartzarenite with mainly local provenance that locally includes carbonates ± mafic volcanic flows; (3) abrupt but conformable transition to basinal dark shales and overlying platformal carbonates that pass upward into siltstones and sandstones that record gradual emergence of the platform. Sandstones within this assemblage display a substantially different detrital zircon provenance signature dominated by early Paleoproterozoic zircons, with grains as young as 1.95 Ga; (4) unconformably to conformably overlying immature marine sandstones, including turbidites, with a significant component of 2.0–1.9 Ga detritus probably derived from a combination of local and distal sources. The thickness and relative compositional maturity of the basal lithotectonic assemblage 1 records a protracted period of enhanced weathering on a slowly subsiding but stable supercontinent (e.g. Kenorland). This was followed by mafic volcanism and marine transgression, consistent with partial rifting of the Rae domain and crustal extension attending supercontinent break-up (lithotectonic assemblage 2). Strata of lithotectonic assemblage 3 record basin flooding and deepening followed by platformal sedimentation along the margins of extended continental blocks. Assemblage 4 is interpreted to represent deposition in foreland basins during early amalgamation of Laurentia (part of Nuna) at ca. 1.9 Ga. The stratigraphy and detrital zircon geochronology of the Hurwitz Group, which overlies the Hearne domain, is broadly similar to the supracrustal sequence of the Rae domain, but differs through the presence of basal diamictites and lack of 2.5 Ga detritus, a major local source in the Rae. Our data suggest that the Rae and Hearne domains were assembled together by max. 1.91 Ga (i.e. max. age of deposition of the uppermost Hurwitz and Amer groups). The Paleoproterozoic stratigraphic assemblage framework for the Churchill Province compares well with that of other cratons derived from break-up of Kenorland and ultimately amalgamated in Nuna. Examples from Laurentia include supracrustal rocks that overlie the southern margin of the Superior Province (Southern Province, e.g. Huron Supergroup, Animikie Group, Marquette Range Supergroup, Whitewater Group and Mistassini-Otish Group). The Paleoproterozoic assemblages of the Southern and Churchill provinces exhibit first-order stratigraphic similarities that indicate a shared history of stable continental sedimentation followed by rifting, basin opening and basin closure.

Water use efficiency and economic feasibility of growing rice and wheat with sprinkler irrigation in the Indus Basin of Pakistan

With a population of more than 150 million, Pakistan cannot meet its need for food, if adequate water is not available for crop production. Per capita water availability has decreased from 5600 m 3 in 1947 to 1000 m 3 in 2004. Water table has gone down by more than 7 m in most parts of the country. Present need is to identify and adopt measures, that will reduce water use and increase crop production. This study was conducted in farmers’ fields during 2002–2004 to evaluate the water use efficiency and economic viability of sprinkler irrigation system for growing rice and wheat crops. Yields and water use were also measured on adjacent fields irrigated by basin flooding, which were planted with the same crop varieties. Sprinkler irrigation of rice produced 18% more yield, while reducing consumption of water to 35% of that used in the traditional irrigation system. Sprinkler irrigation of wheat resulted in a water use efficiency of 5.21 kg of grain per cubic meter of water used compared to 1.38 kg/m 3 in the adjacent flooded basins. Benefit–cost analysis showed that adoption of rain-gun sprinkler irrigation for rice and wheat is a financially viable option for farmers. While these findings show large potentials for improving water use efficiency in crop production they also indicate that a large portion of the water applied in traditional flooded basin irrigation is going to groundwater recharge, which has high value near large cities which draw their water from the aquifer.

Review of Environmental Hydraulics and Sustainable Water Management, Proceedings of the 4th International Symposium on Environmental Hydraulics and the 14th Congress of Asia and Pacific Division, International Association of Hydraulic Engineering and Research, edited by J. H. W. Lee and K. M. LamEnvironmental Hydraulics and Sustainable Water Management, Proceedings of the 4th International Symposium on Environmental Hydraulics and the 14th

This dual symposium and congress brings back wonderful memories from Hong Kong. The daily 8:00 p.m. Symphony of Lights from the Avenue of Stars surely enlightened all participants from over 35 countries. The venue was organized by the Department of Civil Engineering at the University of Hong Kong. The organizing committee, and in particular J. H. W. Lee and K. M. Lam, are to be commended for this first-class venue. By joining the symposium with the congress, about 350 participants attended and shared research and application results in a multiple parallel sessions setting. The heavy two-volume set of printed proceedings was available at the registration desk, along with a poster showing an aerial view of Hong Kong. The objective of the joint conference of the International Symposium on Environmental Hydraulics and the International Association of Hydraulic Engineering Asia-Pacific Division was to bring together scientists, engineers, and researchers with a common interest in water environment and hydraulic problems. The conference aimed to provide forum for the exchange of ideas and experiences on recent developments in environmental hydraulics and water management issues. The main theme of the conference was “Sustainable Water Management in the Asia-Pacific Region.” The Asia-Pacific rim faces many water environment challenges in the new millennium. Examples include the assurance of an adequate and clean water supply, the prevention of urban and basin flooding, the search for a sensible sewage strategy, the achievement of sustainable water quality to enhance quality of life, and the protection of aquatic and coastal fisheries. Water problems will be associated with increasing complexity and wider scope brought about by issues like global climate change, massive urbanization, economic risks in infrastructure investments, crossborder pollution, and government policies. The proceedings include 300 papers selected from 400 abstract submissions, prepared in two volumes. Volume 1, entitled “Environmental Hydraulics,” contains 2 keynote lectures, 7 invited lectures, and 153 contributing papers. The papers cover a broad

English

The Irwin Syncline bituminous coal basin has been extensively underground mined with numerous complexes (>95% mined over a 240 km 2 area; Pullman-Swindell, 1977). Earlier work in the Irwin Syncline demonstrated the benefit of dividing the basin into smaller sub-basins based on equilibrium flow conditions established over the past 30 years (Winters et al. 1999; Winters and Capo, in press). MODFLOW numerical modeling was undertaken to quantify the hydraulic relationships within the basin and to corroborate sub-basin delineation over time (~ 5-15 yrs) as post-mining equilibrium hydraulic conditions develop. Boundary conditions are imposed by (1) the coal outcrop, which limits hydraulic influence, (2) the low hydraulic conductivity of the coal seam floor (typically clay, K~10 -8 cm/sec), and (3) large surface water bodies. Because of these constraints, recharge can be assumed to emanate primarily from infiltration through the overburden rocks. Basin discharge can be directly measured from the large discharges that developed following basin flooding. In the Irwin basin, the overburden rocks range in thickness from 0 m at the outcrop to 200 m in the interior. Overburden units were modeled as four distinct hydraulic conductivity zones that correspond to classic mine subsidence profile models (Singh 1992). Initial model results indicated that mine water is discharging through the intervening overburden to the Youghiogheny River, which overlies the southwestern portion of the basin. To calibrate the model, 15 mine pool monitoring points from the 1970's were used to establish known hydraulic head elevations in the northern 2/3 of the basin. Hydraulic head elevations in the southern 1/3 were determined from current pumping elevations at two treatment plants in the area. Preliminary results from the calibrated model demonstrate the hydrologic impact of interior coal mine barriers on the flow regime and confirm that the largest discharges (Q >0.18 m 3 /s) are the dominant influence on the flow system. Future modeling efforts will concentrate on sensitivity analysis of recharge and other hydraulic parameters and on refinement of methods used for modeling the mine-void aquifer system.