River Passes Research Articles

Utilization of Sentinel-1 Imagery for Mapping the Distribution of Floods in the Putussibau Kota Subdistrict and Surrounding Areas

Floods are a disaster that often occurs in the Putussibau Kota sub-district, West Kalimantan, because of its location where the Kapuas River passes. However, flood disaster mitigation efforts in this area are often hampered by the lack of information on flood distribution maps and impact predictions. This research utilizes the change detection and thresholding (CDAT) method applied to Sentinel-1 SAR data to map the distribution of floods in the Putussibau Kota sub-district and its surroundings, as well as analyze its impact on infrastructure and population. Next, the impact of the flood is calculated using an overlay technique between the flood map and the exposure map. The research results show that the flood distribution map for the August 2021 event had an accuracy of 0.76 and a kappa coefficient of 0.52. Next, the results of the flood impact evaluation showed that 37 km of roads, 2,700 buildings, and 11,700 people were affected by this incident. This analysis can be used to assist local governments in future flood mitigation efforts.

Flood Modelling of Premulung River, Bengawan Solo

Premulung River or commonly known as Kali Premulung is one of many branches of Bengawan Solo River in its upstream area. This river pass through one of the most historical cities in Central Java, Surakarta. The overcapacity of this river leads to flood event that has a negative impact on humans. The purpose of this research is to analyze the Premulung River capacity and simulate the flood caused by rainfall design. The hydrological matter was analyzed using Hydrognomon and HEC-HMS while flood modelling was analyzed using HEC-RAS software one- and two-dimension (1D & 2D) simulation. Model calibrations were carried out based on historical flood events (depth, duration, and area of inundation) and local interview due to data limitation. Based on the simulation, the flood modelling shows that the current capacity of Premulung River cannot accommodate its peak discharge for two (Q2) and twenty years (Q20) return period flood. There are two main spots identified flooded due to Q2 flood with depth varies from 40 to 80 cm and duration from 4 hour to 7 hour. For Q20 flood, there are also two same spots identified flooded with depth varies from 1.2 m to 1.8 m and duration from 6 hour to 9 hour. The result of this study can be a reference for flood dike design in the future which still require further detailed investigation.

Penentuan Status Mutu Air Sungai Wrati Pasuruan Jawa Timur dengan Indeks Kualitas Air

The Wrati River is located in Pasuruan Regency. This river crosses three sub-districts and six sub-districts, with a total distance of 13.6 kilometers. The subdistrict through which this river passes has land use for household, agricultural, and industrial purposes. These activities hurt rivers, causing pollution and decreasing water quality. Determining water quality status is very important to understand the suitability of river water for various purposes. Understanding water quality can be fundamental information for managing and preventing river pollution. The pollutant index approach used in this research refers to the guidelines in the Decree of the Minister of the Environment Number 115 of 2003. The research results show that the water quality of the Wrati River from upstream to downstream is included in the lightly polluted category at each sampling point, with an index value of 4.94. The main factor causing light pollution in Wrati River water is the excessive phosphate content and other parameters that exceed the specified quality standards. Based on the findings of this research, waste management efforts need to be made to improve the quality of this river water.

Hydro-chemical Study of the Water Resources in the Area between Kifl and Samawa, in the Southwest of Iraq

The study area is of high socio-economic importance. It is characterized by the dependence of most of its inhabitants on agriculture as a basic resource for life, the water, and hydrological status play an important role in the social and economic stability of its inhabitants. Euphrates River passes in the area and is split into two branches: Sabeel and Atshan. The quality of the river water deteriorated very quickly as it passes through the area, where Total Dissolved Solids increases up to 3000 mg/l. The study aims to determine the characteristics of surface and groundwater in this region and their mutual relationship. (113) samples in 2019, were collected from rivers, drainages, springs, shallow and deep wells, and lakes. Main Cations (Ca+2, Mg+2, Na+1, K+1) and anions (Cl-1, SO4-2, HCO3-1, CO3-2, NO3-1) and Boron were analyzed in addition to the physio-chemical parameters (pH and TDS). The results showed that there is no or at least a very weak relationship between the groundwater in the area and the water of the Euphrates River. In addition, there is no effect of this shallow salty groundwater on the quality of the river’s water. On the other hand, the relations showed that there is a strong correlation between drainage water and Euphrates River water quality, which indicates that drainage is a source of added salinity to the river water. The study recommends that appropriate management should be implemented for the water of the Euphrates River in its two branches (i.e. before entering Samawa city) by maintaining fairly high river levels to stop any possibility of water drainage flow in it in the future. It is necessary to address the situation of all drainages scattered in the region, that flow directly into the Sabeel River, by transferring it to the eastern Euphrates drainage, and the volumes of water from these drainages must be compensated to the Euphrates River.

Handumanan sang Ulian (Memories of Ulian): The River Residents’ Sense of Place

This interpretivist-symbolic interactionism study aimed to document the sense-of-place memories among the residents living near or alongside the Ulian River in the Municipality of Lambunao, Province of Iloilo, Philippines. It was grounded on the assumptions surrounding the epistemology of constructionism and the theoretical research perspective of interpretivism-symbolic interactionism. Specific theories pertaining to Sense of Place and Memory were also anchored by this study. Fifteen participants from seven barangays in the Municipality of Lambunao, where the Ulian River flows or passes, took part in this study. They were determined through purposive sampling. Narrative inquiry was used as the methodology of the study, and thematic analysis was applied as a method of analyzing the narratives. After all needed information was gathered through interviews, the data were transcribed, coded, and then analyzed, thus resulting in the formulation of fifteen narratives capturing the sense-of-place memories of Ulian River residents. It was found out that based on the gathered, analyzed data, there were five themes pertaining to the sense-of-place memories of the Ulian River residents. These themes are the river as a food source, the river as a venue for livelihood activities, the river as a place for recreation and extension of household chores, the river as a passageway, and the memories of the river in the context of change.

Remote sensing-based structural and functional assessments of Phragmites australis diebacks in the Mississippi River Delta

• Extensive wetland changes can be caused by abiotic and biotic stressors. • Changes in wetland structure and condition can significantly impact vital navigation, flood risk, and ecosystem health services. • Remote sensing and hot spot analyses were used to measure episodic disturbance impacts on wetland condition. • The results show remotely collected data can provide enhanced spatial and temporal measures of wetland plant extent and condition as a function of landscape level dynamics. The Lower Mississippi River Delta (MRD) is dominated by Phragmites australis which provides a stabilizing force, protecting marsh communities from erosion and storm-related impacts. The MRD has experienced recent die-offs of Phragmites stands, which have coincided with a number of abiotic (hurricane and water-level) and biotic ( Phragmites scale) stressors. During this event, previously healthy stands have died or experienced stunted growth, resulting in conversion to replacement species or to open water. This study utilized remote sensing methods to (1) evaluate changes in Phragmites health and distribution in the MRD through time; (2) assess changes in plant cover and floristic quality before, during, and after the dieback event; (3) evaluate changes in landscape patterns (i.e., percentage of landscape, patch density, total edge, and aggregation index); and (4) evaluate changes in channel length and width as a function of the dieback event. Normalized Difference Vegetation Index data showed an active delta landscape with below typical plant biomass/health in periods of hurricane and dieback impacts, with recovery to health values more typical for the MRD after the dieback event. Vegetation species level assessments showed the MRD landscape experienced decreasing coverage and floristic quality during the disturbance periods, and low and nominally increasing vegetation cover and quality through the dieback and recovery periods. Landscape metrics showed similar trends, where wetland areas that experienced event-related stress during the hurricane and dieback periods, showed some level of rebound during the recovery period. And finally, bank-line change analyses showed a significant increase in the rate of shortening and widening of the Mississippi River Passes since the die-back event began. This study serves as a methodological basis for deriving vegetation trend assessments and integrating those results with landscape metrics to prioritize areas of interest; all of which are essential for effective management and mitigation of aquatic nuisance vegetation.

Radiogenic heat production from natural radionuclides in sediments of the Tigris river in Mosul City, Iraq

In this paper, the concentration of the activity of natural radionuclides is represented by 238U, 232Th and 40K. This concentration was measured by gamma spectroscopy, which was used to determine and calculate radioactive heat production for all radionuclides and their distribution pattern in the sediment samples from the Tigris River in Iraq. The results showed that the activity concentration of these radionuclides was within the allowed limits by the UNSCEAR. Field observations show that the sediments occurred due to the weathering of pre-existing sedimentary rocks that make up the area's geology. The estimated average radiogenic heat production rate was 0.3634 µW/m³. It ranged from 0.2430 to 0.6453 µW/m³, and within the internationally permissible limits, the radiogenic heat production rate in Tigris River sediments was low. It is recommended to conduct a comprehensive radiometric survey to cover all the areas through which the Tigris River passes in Iraq. It will help characterise the radiogenic heat produced for each geological area.

Studi Mutu Air Sungai Cibaligo Kota Cimahi Provinsi Jawa Barat dengan Metode Indeks Pencemar

Cibaligo River is the polluted rivers in Cimahi City. The river that flows through three districts and 6 sub-districts in Cimahi City catchment area of 666.19 hectares of watershed with a total length of 7 km. The land use of the district through which this river passes is domestic, trade, agriculture, livestock and industry whose waste will end into the Cibaligo River. The impact of these activities causes the river to be polluted and a decrease in water quality. The purpose of this study was to determine the status of water quality from upstream to downstream which represents the transition, dry, and rainy seasons. Knowledge of water quality status can be used as basic data for controlling water pollution in rivers. The pollutant index (IP) method used in this study is in accordance with the Decree of the State Minister for the Environment Number 115 of 2003 concerning guidelines for determining water quality status. The results showed that the water quality status of the Cibaligo River from upstream to downstream represented that each season was categorized as heavily polluted with the highest index value being in the rainy season at the downstream point. The main contributor that causes river water to be heavily polluted is domestic wastewater, especially the presence of total coliform and fecal coliform that exceed the established quality standards. Based on the results of the research, efforts to tackle domestic waste are needed to improve the quality of this river water.

On the road: The novice munshi’s view of inter-imperial North India

This article analyses the diary entries made by a Persographic secretary (munshī), Aḥmad ʿAlī, who was employed by a retiring East India Company official to write an account of the journey they made together in 1780 across North India from Lucknow to the Mughal imperial capital in Delhi and back. Much of the landscape that they traversed—including a cluster of qasbahs, river passes, forests and fields—was formerly governed by a confederacy of Rohilla Afghans from 1737 to 1774. By 1780, however, this region was marked by the absence of well-defined, enduring state structures and witnessed an abundance of overlapping political claims. Under such conditions, Aḥmad ʿAlī, a novice secretary from this region who lacked access to major scholarly networks or courtly circles, found himself uniquely placed to observe and document the micro-level political and historical changes that he had lived through. Unlike his courtly counterparts, he witnessed transformations at a remove from both imperial politics and the regional courts that had developed through the eighteenth century. Rather than to a state or a single political project, his locus of service was aligned with the world of independent military entrepreneurs and their households, which were strewn across a region that he knew well. Questioning the view that secretaries were primarily cyphers of courtly culture or bureaucratic imperatives, the following pages demonstrate that while Aḥmad ʿAlī served his individual employer, he could imagine politics and history outside the constraints that came with corporate political affiliations, as a figure who was new to the work of secretarial penmanship and a seasoned bearer of textured regional knowledge.

Priorities and Preferences in Water Quality Management - a Case Study of the Alster\xe5n River Basin

Sweden is a decentralised country where local managers, who are key actors in water management, often deal with relatively difficult prioritisations, tradeoffs and conflicting goals. Many of these challenges relate to the effective implementation of the European Union Water Framework Directive. As an input to these challenges, the present paper elicits and analyses local and semi-local citizens’ preferences for water quality attributes related to the European Water Framework directive in a river basin located in southeast of Sweden. Based on a choice experiment tailored to the case study area, the paper analyses preferences for selected attributes based on real criteria for ecological water status in the implementation of the directive. The target population lives in the municipalities through which the river passes, or in municipalities neighbouring those. Despite this spatial proximity to the river, the analysis reveals limited knowledge and interest in matters related to the environmental quality of the river. There is no evidence that preferences differ between respondents with regard to experience or knowledge about the water basin, nor with regard to recreational habits in the area. These results offer input to local water management by providing information about preferences for explicit water quality attributes.

A numerical study of sediment dynamics over Sandy Point dredge pit, west flank of the Mississippi River, during a cold front event

Sediment transport over Sandy Point dredge pit in the northern Gulf of Mexico during a cold front event in November 2014 was examined using a finely resolved numerical model. The Delft3D model was used to perform numerical experiments that simulate the effect of wind-generated waves, wind-driven currents, river discharge, and tides on sediment dynamics in Sandy Point dredge pit. The hydrodynamics and sediment models were validated and calibrated using field data of current, wave, water level, and suspended sediment concentration. Two potential sources of sediment were examined: fluvial sediment from the Mississippi River and resuspended sediments from the seabed. Results showed that during a cold front, shear stress from wave motions played a significant role in the resuspension of sediments in Sandy Point dredge pit. The maximum cold front-related wave impact on sediment resuspension could increase near-bed sediment concentration in Sandy Point dredge pit by 20–50 times. In addition, the results suggest that the primary source of sediment for Sandy Point dredge pit during a cold front was resuspension from the ambient seabed due to increased bottom shear stress by wind-induced waves and strong southward wind-driven currents. Currents dispersed sediments from the Mississippi River passes and inhibited riverine sediment supply from Sandy Point dredge pit. Results also showed that cold fronts contribute 16%–24% of the annual sedimentation in Sandy Point dredge pit.

The Primeval Cosmic River and Its Ecological Realities: On the Curatorial Project Danube River School

As the longest river in the heart of the European continent, the Danube has been a recurrent topic for artists, writers, poets, filmmakers, and theorists, and whether their accounts linger in the national realm of one of the ten countries through which the river passes, or follow its transnational flow, Anthropocentric undercurrents can regularly be traced in their narratives. Uncovering the environmental history of the Danube, featuring river-centered artistic practices, and investigating the potential for an integrated ecological future of the river were at the core of the interdisciplinary curatorial project the River School, organized by the Translocal Institute between 2013 and 2015. This article investigates ecological challenges to the traditional cultural approaches to the Danube, which reflect the social and political logic that turns the river into a marker of geopolitical struggles, a route for conquest, and a delimiter of national territory, as well as a site for the expression of cultural supremacy. Focusing on the insights provided by the work of contemporary artists, also explored are the potential of the experiential aspect of river research and multispecies perspectives, specific moments in the river’s environmental past and their place in social and political upheavals, and the emergence of ecologically attuned approaches in policy, behaviors, and cultural production.

Priorities and Preferences in the Implementation of the European Water Framework Directive - A Case Study of the River Alsterrn

This paper elicits local and semi-local citizens’ preferences for water quality attributes explicitly related to the water framework directive. A river basin in southeast of Sweden is used as a case study. The sample consists of 502 respondents living in the municipalities through which the river passes, or neighboring municipalities. By the use of a choice experiment tailored to the specific case study area, the paper analyzes public attitudes and willingness to pay for selected attributes related to water quality management. The attributes and their corresponding levels are based on real criteria for ecological water status, used in the implementation of the WFD in the river basin. Although participants live in or close to the catchment area, the results reveal a general lack of knowledge and interest in matters related to the environmental quality of the river. All attributes included in the choice experiment proved to have a statistically significant impact on the choice probabilities. There was however no significant evidence that the preferences differ between respondents with regard to self reported previous experience or knowledge about the water body, nor with regard to differences in recreational habits in the area. The results can potentially be used as inputs in practical policy making with its inevitable trade offs and priorities.

Monitoring of Tirana River and the Margin of Data in Urbanized and Non Rezidental Area

Tirana River is one of the main branches of Ishmi river and serves as collector for wastewater discharge, for the capital city and its surrounding rural areas. This river created the north administrative border of Tirana and it’s formed from mountainouse conflux in Zall-Dajt area. Besides increasing the amount of sewage discharge into the river, as a result of population growth, it is a fact that in Tirana river solid waste from non-responsible businesses and different urban wastes are being deposited. The purpose of this study is to assess the microbiological quality of Tirana river by collecting reliable information about conditions in different area wherever the river course outside and inside the Tirana city. Samples were taken at four different points during year 2012-2013. The river is tested for indicators of pollution such as Streptoccocus faecali and Escherichia coli as well as the presence of actinomycetes. Microbiological contamination tests show relatively large water contamination, especially in three areas where the river passes in residential area. Bacteria are transported to the River via storm water, catch basins, sediment, runoff, discharges, and spills. Larger amounts of bacteria reach the river when surrounding lands are more highly developed or "urbanized." The high level presence of these microorganisms indicates that the water quality of the river is very bad according to standards, presenting a risk to health of all the organisms that inhabit the sweet waters. River areas in considerable distance from residential areas, show microbiological level lower than in those close to residential areas. It is noticed also, a growth of temperature and TDS. This growth was more evident during raining days for TDS and temperature during drought periods of monitoring.

Late-Holocene fluctuations of the Bear River Glacier, northern Coast Ranges of British Columbia, Canada

During Holocene advances of the Bear River Glacier, in northwestern British Columbia, ice pushed against a bedrock slope on the north side of Bear River Pass as it was being diverted eastward and westward along the pass. The result is a series of till sheets plastered against the rock slope and separated by wood mats. This sequence of tills provides an unusually detailed record of early-Neoglacial history and shows that Neoglacial expansion in the northern Coast Mountains began earlier than previously known. Moraines show the extent of ‘Little Ice Age’ expansion, and documents related to the long mining history of the area provide records of post-LIA recession. The oldest deposits in the area are a small lateral moraine outside of a prominent LIA moraine, and a till in the pass older than c. 3500 14C yr BP. The small moraine is undated; it may be equivalent to the latest-Pleistocene Crowfoot Advance which produced similar moraines in the southern Coast Mountains and eastern Cordillera. Wood mats in the pass show that Neoglacial advances occurred at c. 3700, 3500, 3300, and 1000 14C yr BP; each advance was slightly more extensive than the previous one. Documentary evidence indicates that the pass was still filled with ice in 1913, and diverging both eastward and westward, but glacier retreat has been rapid since then. Retreat from the pass in the mid-20th century resulted in the creation of Strohn Lake, through which meltwater from the glacier passes; a complicated lake history includes switching of discharge from eastward to westward and a series of jokuhlaups that damaged highway infrastructure to the west. A comparison of the history recorded at Bear River Pass with that recorded at the Todd Icefield 15 km to the north shows that different components of glacial history are preserved in different places, and many sites need to be examined to obtain a relatively complete regional history.

Mountain Pass Slope Failure Retrofitted with a Half Viaduct Bridge Structure, South Africa

The Garden Route, one of the main tourist attractions and also a major national road on the south coast of South Africa, experienced abnormally high rainfall in August 2006. A major slip failure occurred in one of the road cuttings, known as Kaaimans River Pass, which severely damaged the roadway. The owner (South African National Road Agency Ltd.), immediately took measures to restore this vital link in the national road network. Several preliminary concepts were developed by the project team which included bridge and geotechnical specialists from the owner and the project-consulting engineers. These included a tied pile anchor wall, a tied mechanically stabilized embankment and a half-width pre-cast beam bridge structure. The selection of the most suitable option relied heavily on the geotechnical conclusions by specialists from the project-consulting engineers, after an extensive drilling programme was undertaken to investigate the competency of the underlying rock substrata. A modified version of the first concept was finally decided upon, as this was considered to provide the optimum solution, considering interaction with the adjacent road formation as well as the bedrock profile.uThe new viaduct is supported on eight 1200 mm diameter reinforced concrete oscillator bored piles approximately 14 m long, spaced at 8 m centres and socketed 4 m into competent rock. The superstructure comprises a 7 m wide, 60 m long cantilevered deck that is counterbalanced by an integrated buried jockey slab and supported on the piled substructure. This configuration eliminated a problematic longitudinal joint. The structure is anchored with re-stressable rock anchors, ensuring the stability of the structure and rock formation. In order to minimize the movement between the roadway and structure, the jockey slab is also tied down with anchors. (A)

Systematics of the southern African genus Ixia (Iridaceae). 1. The <i>I.</i> <i>rapunculoides</i> complex

Field and laboratory investigation of the six varieties of Ixia rapunculoides Delile (recognized in the current revisions and flora accounts of this southern African genus of some 65 species) show that a revised taxonomy better reflects the biology of the complex. The complex is defined by the funnel-shaped perianth tube, filaments fully and anthers partly included in the perianth tube. Our conclusions indicate that I. rapunculoides (currently var. rapunculoides) is restricted to the western Karoo and has broad, leathery leaves, a short perianth tube, mostly 5.5-8.0 mm long, and half nodding blue-mauve flowers. Plants currently referred to I. rapunculoides var. flaccida G.J.Lewis, include four sets of populations that we regard as two separate species. These are: I. flaccida with small, short-tubed white- or pale blue-flushed flowers, sofl-textured leaves and corms with basal cormlets from the Olifants River Valley and nearby; and I. sobolifera from the Western and Little Karoo, which has linear leaves, nodding spikes and flowers and corms with stolons. We divide I. sobolifera into three subspecies: subsp. carnea with pink flowers, is restricted to the Bokkeveld Plateau and nearby; subsp sobolifera with slate-blue flowers occurs in the Klein Roggeveld and nearby; and subsp albiflora with strongly scented white flowers occurs in the central Little Karoo. The taxon called I. rapunculoides var. namaquana (L.Bolus) G.J.Lewis, defined by a longer perianth tube, mostly 13-16 mm long, horizontally oriented, white, pale lilac or pink flowers and few-flowered lateral branchlets. is treated as I. namaquana, first described by H.M.L. Bolus in 1931. Plants referred to this taxon from south of its range at Hex River pass and nearby, however, have fully included anthers, a longer perianth tube. 16-20 mm. and ascending purple-pink flowers with a white cup and are referred to the new I. oxalidiflora. Two more varieties, I. rapunculoides var. subpendula G.J.Lewis and var. rigida sensu G.J.Lewis, which have upright flowers and distinctively branched stems are treated here as I. divaricata and I. contorta. Plants in the past included in var. rapunculoides from the Klein Roggeveld, south of the range of typical I. rapunculoides, have a longer perianth tube. 10-14 mm long, and attenuate, slightly lacerate. 5-veined. dry. rust-tipped bracts and comprise the new I. lacerata In addition, plants from streambeds in the Roggeveld that have large, white flowers, are not included in current accounts of the genus, and also represent a novel taxon, I. rivulicola. Lastly, I. rapunculoides var. robusta G.J.Lewis, the range of which falls entirely within that of var. rapunculoides and is usually sympatric with it. has pink flowers of similar structure, but four or five leaves and deep-seated corms with a collar of coarse fibres around the stem base. We raise this plant to species rank as I. robusta

Cation, anion, conductivity, and absorbance characteristics of Tarawera River seepage water entering the Western Drain, Eastern Bay of Plenty, New Zealand.

Two pulp mills, located downstream of the township of Kawerau, in the Eastern Bay of Plenty region of New Zealand, have for more than 35 years, discharged effluent waters to the Tarawera River. Upstream of the mill discharges river water has a high quality, while downstream water is highly coloured and characterised by diminished dissolved oxygen (BOPCC 1985, McIntosh 1995, Rutherford et al. 1991, Rutherford 1991) and by the presence of significant levels of resin acids (Wilkins et al. 1996a, Judd et al. 1996). During its passage across the Western Rangitaiki Plains the Tarawera River is constrained behind stop banks. At two points the river passes in close proximity to the Western Drain. This drain is one of a series of canals and drains which collect water from surrounding farmland and return it to the Tarawera River shortly before its entry to the sea near the township of Matata.

Discharge of mercury from the Wairakei geothermal power station to the Waikato River, New Zealand

The Wairakei geothermal power station on the west bank of the Waikato River 10 km north of Lake Taupo, New Zealand, discharges a warm mixture of cooling water and geothermal steam condensate to the river. This discharge contains at least two chemical species of mercury (Hg): elemental mercury (Hg0) at a mean concentration of 42 μg m−3; and other unidentified species, not reducible by acidic stannous chloride, at a mean concentration of 79 μg m−3. The annual discharge to the river of total Hg is 46.5 kg (CI95 42.0–51.8) of which 19.3 kg (CI95 18.3–20.0) is Hg0. On average 53 g d−1 of Hg0 is discharged from the Wairakei station to the river and 50 g d−1 of Hg0 flows out of Lake Aratiatia, the reservoir formed for the Aratiatia hydro‐electric power station 3 km down‐stream from the Wairakei station. The residence time of the condensate in Lake Aratiatia varies between 1.5 h at high river flow and 12 h during winter when water is accumulated in the lake overnight. The warm condensate initially floats on the surface of the river but only a small proportion of the Hg0 is lost to the atmosphere. Furthermore, the short residence time of the condensate in the lake probably limits the extent to which other mechanisms can remove Hg0 from the river water. For these reasons it is concluded that most of the Hg0 discharged to the river from the Wairakei station remains as Hg0 in the water flowing out of Lake Aratiatia. Fine‐grained bed sediments in Lake Aratiatia are an insignificant sink for Hg because of their very small area and relatively low total Hg concentrations. It seems likely, therefore, that the non‐reducible forms of Hg discharged with the condensate also remain in the river water and pass out of the lake.

Passages: Three Poems at Thorn Portal

Passages: Three Poems at Thorn Portal