Showing papers on "Saline water published in 1988"

Trends in Nutrient and Oxygen Conditions Within the Kattegat: Effects of Local Nutrient Supply

Abstract: The Kattegat forms the outer part of the Baltic estuary. It is characterized by a stable two-layer stratification maintained by approximately equal supplies of low saline water from the Baltic and high saline oceanic water from the Skagerrak. The nutrient supply to these waters increased rapidly during the past decades and oxygen deficits have been reported from different parts of the estuary. In this paper, we have calculated trends in nutrient and oxygen concentrations within the surface and deep waters of the Kattegat and adjacent waters. This has been done with available data for the past decades, with reference to nutrient supply and phytoplankton production. Oxygen concentrations within the deep water decreased from 4·58 to 4·08 ml l−1 between 1971 and 1982, indicating a 50% increase in oxygen consumption. Concentrations of Tot-N, Tot-P and inorganic nitrogen increased simultaneously, both in the surface water during the winter and in the deep-water during the summer. Changes in Tot-N and Tot-P were dominated by the Baltic water, while local supply to the Kattegat dominated the changes in inorganic nitrogen. Increases in Tot-N and Tot-P suggest a successively increasing biomass. The importance of local nutrient supply to the Kattegat was studied by comparing expected nutrient concentrations within the surface water (due to exchange with adjacent waters) with actually observed concentrations.

Distribution of bivalve larvae at a frontal system in the James River, Virginia

Abstract: The James River is the southernmost of the major subestuaries of the Chesapeake Bay, USA. A frontal system develops on the early flood tide in the Hampton Roads region of the lower James. This system, together with a cyclonic gyre in Hampton Roads, is in part responsible for partial retention of downstream-flowing water in the estuary and it's injection into deeper, upstream-flowing water. The role of the frontal system in retention of bivalve larvae in the James was investigated In a 2-part study: a field exammation of larval distr~bution versus depth along a transect across the front in relation to salinity and temperature of the converging and diverging water masses, and a laboratory examination of the ability of oyster Crassostrea virginica larvae to swim in and through salinity gradients comparable to or greater than those encountered near the frontal system. Field studies indicate that larvae are passively transported through the frontal system and plunge to depth as the more saline water in which they are entrained encounters less saline water The deeper, more saline water flows upstream as it leaves the frontal system. Laboratory studies demonstrate that both straight hinge stage (mean length = 7 5 ~ ) and umbo stage (mean length = 157.5 to 159.7 pm) larvae actively swim through a salinity discontinuity of 3 %D when exposed in a column of 22 960 water overlayed by 19 9b. water (extreme values charactenstic of bottom and surface water at the frontal system). Further, their mean rates of vertical movement (0.37 to 1.02 mms-') illustrate the ability of larvae to move through the depth of the water column in the James in less than one tidal cycle. Pediveliger stage oyster larvae (mean length 317.2 pm), by contrast, restricted swimming to small but frequent excursions above the bottom in the laboratory apparatus and did not swim through the salinity interface. Following passive transport through the frontal system in the lower James straight hinge and umbo stage larvae may employ active depth regulation to redistribute throughout the water column; however, pediveliger stage larvae probably remain near the sediment-water interface.

Hardness in Drinking Water

Abstract: Total hardness and concentrations of calcium and magnesium, and partly detection of nitrous ion and ammonium ion in tap water, well water, mineral water drinks, etc., in the summer of 1987 in Tokyo and the around areas, and the survey of taste for mineral water drinks were investigated. The average hardness in tap water and well water were about 69 ppm and 96 ppm (as the amount of CaCO3), respectively, and the average concentrations of calcium and magnesium were about 19 ppm and 5 ppm, respectively, in tap water and about 22 ppm and 8 ppm, respectively, in well water. Tap water stored in a water tank of a building showed rather low hardness, compared with tap water unstored in the tank. Nitrous ion or ammonium ion was detected in 9 out of 13 the stored tap water samples and more than halves of well water and natural water samples. It indicates that tap water in the water tank and ground water were contaminated. The order of good taste for mineral water sample (total hardness 27-650 ppm) was almost the same as that of lowness of water hardness.

Method of growing and harvesting microorganisms

Abstract: A process and system for growing and harvesting algae of the genus Dunaliella, along with their associated bacteria, either in a body of saline water having extensive surface area and shallow depth, or in a tank. In the former the algae are grown in a saline body of water, caused to accumulate in the upper regions of the body of water by the action of light, and caused to aggregate in the upper regions by outflowing the body of water into a first harvesting location by way of a transition channel wherein the body is changed from being shallow and wide to narrow and deep. The upper regions containing the aggregation of algae and associated bacteria are then separated as a slurry and introduced into a second harvesting location wherein salt is introduced into the slurry so as to increase its density thereby causing the algae and associated bacteria to float on the surface. The algae and associated bacteria are then harvested off the surface as a biomass by skimming or other means. When grown in a tank of saline water the algae and associated bacteria are caused to accumulate in the upper regions by the action of light, the depleted lower regions are discharged from the tank, salt is added to the remaining upper regions thus causing the algae and associated bacteria to float on the surface, and the algae and associated bacteria are then harvested off the surface.

Estimating saline water table contributions to crop water use

Abstract: Not Available – First paragraph follows:Researchers in several western states have found that, under arid conditions, water tables can supply as much as 60 to 70 percent of a crop's water requirement. Use of high water tables reduces irrigation needs, lowers production costs, reduces deep seepage losses, and decreases the volume of drainage water requiring disposal. Successful use of the water table also depends on the soil's water retention and transmitting properties, evapotranspiration (ET) demand, distribution of the plant root system, and salinity and toxic ion effects on crop growth. Under field conditions, many of these factors are part of the overall crop response to the saline.

Electric log interpretation for the evaluation of salt water intrusion in the eastern Niger Delta

Abstract: The Niger Delta (75 000 km2) comprises a thick (up to 9000 m) sequence of clastic sediments subdivided into the Akata, Agbada and Benin Formations in ascending order. Sands of the Benin Formation constitute aquifers which have been exploited for water supply, although in parts of the delta many of them have been abandoned due to high salinity. Interpretation of 267 oilwell logs for delineating the fresh water-bearing aquifers is reported here. While fresh water sands occur at the upper zone of the Benin Formation in most places, saline water sands were found at the upper zone at depths (ranging from 30 to 947 m) in two well-defined areas, underlain by fresh water sands. The saline water is thought to be connate. The fresh water/saline water interface has been mapped throughout the eastern Niger Delta and is found to be deepest (2237 m) 44 km westsouthwest of Port Harcourt.

Nitrogen concentration, ammonium/nitrate ratio and NaCl interaction in vegetative and reproductive growth of peanuts

Abstract: Peanuts (Arachis hypogaea L. cv. Shulamit) grown with NO3− and saline water in hydroponics responded positively to addition of nitrogen (N) in their vegetative growth, but not in desert dune sand. In order to clarify these conflicting results, peanut plants were grown in a greenhouse pot experiment with fine calcareous sand. The nutrient solution contained 0 or 50 mM NaCl and 2 or 6 mM N in the form of Ca(NO3)2, NH4NO3 or (NH4)2SO4. Three replicates were harvested after 48 days (beginning of reproductive stage) and three after 109 days (pod filling). In addition, gynophores were treated with 0, 50, 100, 150 or 200 mM NaCl outside the growth pot to check their sensitivity to salt. Shoot dry weight became greater with increasing NH4+/NO3− ratio. Increasing the N concentration from 2 to 6 mM did not change shoot dry weight of the NH4NO3 or NH4+-fed plants, but caused a reduction in shoot dry weight of NO3−-fed plants. Shoot dry weight was not affected by increasing the NaCl concentration to 50 mM. Salt caused an increase in the number of gynophores per plant and a reduction of the mean pod weight. A NaCl concentration of 100 mM and above reduced gynophore vitality. It is concluded that the salt sensitivity of peanut plants resides mainly in the sensitivity of the reproductive organs.

Mass exchange between mobile freshwater and immobile saline water in the unsaturated zone

Abstract: A profile of tritium concentrations measured in the unsaturated zone in loessial sediments in a semiarid area is interpreted in terms of mobile and immobile water domains, according to a physical nonequilibrium transport model. The mobile domain is represented by percolating fresh water from both rain and irrigation, and the immobile one is represented by isolated fossil saline water pockets. The two domains are connected by partially-saturated narrow passages within dispersed clay minerals. The transport of the mobile water is described by convective-dispersive flow and mass exchange between the two water domains takes place simultaneously. The relevant equations with the given initial - boundary conditions are solved numerically, and the simulated profile is adjusted to fit the measured profile. By taking into account variations of the mass exchange coefficient in relation to matrix characteristics, we were able to obtain an adequate reconstruction of the measured profile. Temporal changes in matrix characteristics are attributed to dispersion kinetics of clays at the interface between fresh and saline waters.

Effect of salinity stress on development of Pythium blight in Agrostis palustris

Abstract: Rasmussen, S. L., and Stanghellini, M. E. 1988. Effect of salinity stress on development of Pythium blight in Agrostis palustris. Phytopathology 78:1495-1497. Salinity stress predisposed cultivar Penncross creeping bentgrass to inoculated plants at an Ec level of 0.5 ds/m. Increased salinity levels cottony blight caused by Pythium aphanidermatum at two temperature apparently affected the bentgrass rather than P. aphanidermatum. regimes. At 25-32 C, complete necrosis of all inoculated plants occurred at Mycelial growth rate of the fungus was increased only slightly by salinity electrical conductivity (Ec) levels of 4.3-7.1 decisiemens (ds) per meter in 2 levels up to 7.1 ds/ m. Zoospore production of P. aphanidermatum and two days, whereas at Ec levels of 0.5-2.8 ds/ m, death occurred within 3 days. At other species of Pythium decreased with increasing salinity levels up to 7.1 25-27 C, complete necrosis of all inoculated plants occurred at Ec levels of ds/m; production was completely inhibited at 14.2 ds/m. 4.3-7.1 ds/ m within a period of 5 days; no death was observed in control or Additional keywords: Pythium catenulatum, Pythium dissotocum. Penncross creeping bentgrass (Agrostis palustris Huds. amended with a NaCl and CaC1 2 solution 1:1 (w/w) to achieve 'Penncross'), a temperate region grass, is widely used throughout electrical conductivity (Ec) levels of 1.4, 2.8, 4.3, 5.7, 7.1, 14.2, and the world for golf course greens, tees, and fairways. Extensive 28.4 decisiemens (ds) per meter (1 ds/m = 640 ppm). The same development of resorts and recreational facilities has expanded the medium (0.5 ds/m) without the addition of salt was used as a use of Penncross bentgrass into tropical, arid, and semi-arid control. Cultures were incubated at 15, 20, 25, and 30 C, and, after climatic regions where nonpotable and saline water commonly are an initial growth period of 12 hr, the radius of each colony was used for irrigation, measured after 24 and 48 hr. There were two replicates of each The sensitivity of Penncross bentgrass to salinity has been salinity value at each temperature regime, and the experiment was documented (15); however, no studies have been conducted conducted three times. regarding the effect of increased salinity on the diseases commonly Effect of salinity on zoospore production. A 9-mm-diameter occurring on Penncross. Cottony blight, caused primarily by disk was cut from a 5-day-old VJA culture of each fungus and Pythium aphanidermatum (Edson) Fitz., is a particularly placed in a 9-cm-diameter petri dish containing 20 ml of NaCl and devastating disease on Penncross bentgrass. Environmental CaCI2 solution 1:1 (w/w) with Ec values of 1.4, 2.8, 4.3, 5.7, 7.1, conditions conducive for disease development include high relative and 14.2 ds/ m. Sterile distilled water was used as a control. After humidity, saturated soils, and daytime temperatures of 30 C or 48 hr incubation at 25 C, all zoospores had encysted and settled to greater (11). The accumulation of salts due to saline irrigation the bottom of the dish. Then 0.1 ml of 10% acid fuchsin was added water may impose an environmental stress leading to increased to each dish to stain the cysts. The total number of zoospore cysts plant susceptibility. Increased disease severity resulting from per plate was determined by counting cysts in 10, 0.5 mm 2 fungicide and herbicide use (6,14), and susceptibility of bentgrass arbitrarily selected sites on the bottom of the dish under a to Curvularia lunata from heat and leaf clipping stress (10), have compound microscope. The total number of cysts per dish was been reported. then calculated by multiplying the mean of the 10 sites by the The objective ofthis study was to determine the in vitro effect of surface area of the bottom of the dish (6,361 mm 2 ) and then

Crude oil dissolution in saline water

Abstract: The solubilities and diffusion coefficients of crude oils having API° ranging from 11 to 28 have been measured in distilled and saline water of 44 g L−1 NaCl at temperatures 25, 35, and 45 °C. A linear relationship was observed between the maximum oil solubilities in distilled water and those in saline water for all the crudes over the range of temperature studied. The Setschenow salting-out parameter was found to be 0.125 independent of temperature and API°. Such a parameter is valuable in estimating the crude oil solubilities in waters of different salinity. An analytical solution for unsteady-state diffusion was done using Fourier series. A linear relationship was found between the diffusion coefficients of oils in distilled water and those in saline water. Observed data for diffusion coefficients of the oils have been correlated in terms of API°, temperature and ionic strength with an average absolute deviation of 2%.

Desalination of saline water

Abstract: Saline water containing a chlorine-containing compound in the form of free chlorine, hypochlorite, etc. which has been added as a disinfectant or antibacterial compound is desalinated by passing the saline water through a semipermeable membrane which is resistant to the chlorine. The saline water is passed through this membrane at a temperature in the range of from ambient to about 50° C. and a pressure in the range of from about 1380 to about 6895 kPA (200-1000 psi). The chlorine-resistant semipermeable membrane comprises an interfacial polymerized condensation reaction product composited on a porous backing support material which has been prepared by contacting a porous support material such as polysulfone with a solution of a diaryl methylene monomer containing at least one amine radical on each aryl nucleus. The coated support material is then contacted with an organic solvent of an aromatic carboxylic acid chloride for a period of time sufficient to form an interfacial polymerized reaction product on the surface of the support material. Following this the composite is then cured at an elevated temperature to form the desired membrane.

Elution of Selenium from Contaminated Evaporation Pond Sediments

Abstract: Selenium-contaminated sediments were collected from evaporation ponds at the Kesterson National Wildlife Refuse in California. Columns of undisturbed, freeze-dried, and air-dried sediments were each leached with deionized water, California aqueduct water, and saline water. Total Se and inorganic Se were measured in the effluent. Following leaching, the sediment cores were sectioned, extracts were prepared using deionized water, and analyzed for total Se, inorganic Se, and selenite using fluorimetric techniques. Selenium remained immobile in the undisturbed sediments, but freeze- and air-drying increased Se mobility. The maximum concentrations of total Se in the effluent from undisturbed, freeze-dried, and air-dried sediments were 32, 7600, and 232 650 nmol L⁻¹, respectively. Microbial activity played an important role in the reduction of Se to immobile and volatile forms. Se recovered in the effluent and from water extraction of the sediments following leaching was highest for deionized water and least for aqueduct water under nonsterilized conditions. The composition of solution did not significantly influence the leaching of Se under sterilized conditions. Introducing Se to previously leached sediments resulted in an increase in water-extractable Se, particularly near the surface. However, when the concentration of added Se was high (31.70 µmol L⁻¹ in this study), the increase in water-extractable Se also occurred at greater depths in the sediments. Contribution from Univ. of California, Davis. Funding was provided by the Univ. of California Salinity/Drainage Task Force.

Evaluation of Hach Fish Farmer's Water Quality Test Kits for Saline Water

Abstract: Hach Company Fish Farmer's Water Quality Test Kits (Models FF-2 and FF-1A) were compared with Standard Methods of analysis by determining dissolved oxygen, carbon dioxide, pH, total alkalinity, total hardness, chloride, total ammonia-nitrogen, and nitrite nitrogen in waters of 0, 17, and 30 ppt salinity. Results indicate that the kits generally are reliable for making routine water analyses of saline waters for practical aquacultural applications.

Application of the threshold concentration concept to irrigation with saline water

Abstract: . The applicability of the ‘threshold concentration’ concept in formulating guidelines for irrigating with saline water was tested under field conditions on red-brown earths from different field experiments in south eastern Australia. Infiltration of water in the field and the effect of rainfall impact were studied using ring infiltrometers and a rotating-disc rainfall simulator. Three threshold concentration lines relating sodium adsorption ratio (SAR) and total cation concentration (TCC) in soil extracts were tested. These lines were based on laboratory tests of soil permeability, spontaneous dispersion and mechanical dispersion. They were found to predict the infiltration problems due to rainfall impact under three different surface soil conditions - bare soil without cultivation, soil with no tillage and complete crop cover, and cultivated soils without any crop cover. Infiltration rates in continuous pasture plots were predicted by the threshold concentration line of spontaneous dispersion except in a high salt treated soil where reduced plant growth affected evapotranspiration and water intake during infiltration.

Microbial process for photohydrogen production from cellulose in high saline water medium

Abstract: A process that is carried out in partly sequential and partly simultaneous steps as detailed below, to build a process, with natural light using wave lengths from 360 nm to 900 nm using solid substrate of carbonaceous substances and one phototrophic bacteria and saline water to produce a rich fuel gas.

Buoyancy powered desalinization plant

Abstract: Air holding spaces are incorporated into a ring attached by arms to a driveshaft supported on sealed bearings in a vessel containing saline water. Air compressed by a blower or air compressor, powered by external power (i.e. prime mover), is injected into the air holding spaces by injectors. The spaces ascend due to their buoyancy, imparting a rotary motion to the driveshaft. Energy developed is transmitted through the driveshaft to an electric generator powering the system control computer, sensors and valves. Energy is also used to rotate a water pump which draws in saline water and pumps it to a saline water tank at the top of the vessel, where it circulates through an array of water holding tubes of thermally conductive material. Heat generated by the compression of the injected air is conducted to the saline water. This heat and the molecular agitation of the water by the ascending air causes the water molecules at the surface to evaporate into the vapor state. Heat is conducted from the vapor, through the conductive tubes, into the saline water. The air, having lost this heat, gives up liquid water, which condenses on the tube surfaces, and falls into a fresh water holding tank. Saline water is delivered to the vessel to maintain water level. Salts are removed by periodic partial draining. All input and output is controlled by a system control computer programmed with the operating parameters, and which receives real-time input from a series of sensors within the system.

Effects on Seal Properties of Changes in Drops Energy and Water Salinity during a Continuous Rainstorm

Abstract: The effect of changes in rainfall energy and water salinity, during a continuous simulated rainstorm, on seal properties was tested in a silty loam soil (Calcic Haploxeralfl with medium (9.0) and low (2.5) exchangeable sodium percent (ESP) values. Saline water (EC = 5 -6 dS m-1) and distilled water were rained at two energy levels: high energy with kinetic energy of 22.9 J mm-1 m2, and low energy with kinetic energy of <0.01 J mm-1 m-2. A seal may be fully or partially developed. The seal formed by a distilled water rain of high energy and sufficient duration is fully developed. A seal formed by rain with low energy, or by high-energy rain of short duration, or by saline rainwater of high energy and long duration, is a partially developed seal. A fully developed seal is stable and its permeability responds only to simultaneous changes in electrolyte concentration and rain energy. Conversely, a partially developed seal is not stable and its permeability responds to changes in electrolyte concentration only.

Observations on the coexistence of fresh and saltwater invertebrates in an inland saltworks

Abstract: SUMMARY The fauna of three excavated trenches in the floor of the dry salt-pan in the Brandfort district of the Orange Free State was investigated. Two were found to contain typical saline water invertebrate fauna such as Artemia sp. and the saltwater rotifer Brachionus plicatilis and were without vegetation, while the third supported dense stands of Ruppia maritima, the salt water rotifer Brachionus plicatilis and a variety of freshwater macro-invertebrates. We concluded that certain freshwater macro-invertebrates are able to tolerate saline water, and that this would give them a competitive advantage over stenohaline invertebrates in semi-arid and arid areas where a range of salinities occur within and among the endorheic pans in the region.

Equations for Complex Relative Permittivity of Saline Water

Abstract: Equations hare been presented to calculate the complex relative permittivity of saline water as a function of salt content and temperature of water. The results obtained from these equations show good agreement with the published measured data.

Seasonal Variation of the Water Type in the Tsushima Current

Abstract: Using the oceanographic data during 196s~ 1983, the seasonal variation of the water type in the Tsushima Current is discussed by analyzing the thermosteric anomaly . By investigating with the index of in salinity, it is shown that the low saline water inflowed through the Korea Strait affects the variations of water type in surface layer from summer to fall. On the sea surface, the value of is affected mainly by the sea surface temperature (SST). However, in summer, is temporarily influenced by the transitional characteristic of the surface salinity. It has the minimum value in winter when the SST is the highest and the sea surface salinity is the lowest. In fall, it decreases as the SST decreases. Specifically, the value of is 779 cl/t in August in the region of Korea Strait and 667 cl/t in September in the East Coast of Korea. These values are larger than that of the Kuroshio where is 622 cl/t in August. This phenomenon is due to the inflow of low saline water into these area during summer. In loom depth, the seasonal variation of the is not so significant as the surface and is mainly dependent on the annual temperature variation. In general, decreases as the Tsushima Current flows to the north.

Processed seaweed and preparation thereof

Abstract: PURPOSE: To prepare processed seaweeds having excellent preservability, exhibiting beautiful green color, having excellent palatability and eatable in raw state without cooking, by heating raw seaweeds in the presence of an alkaline component of plant ash, etc., to effect discoloration of the seaweeds in green color. CONSTITUTION: Raw seaweeds such as WAKAME (Undaria pinnatifida) or laver are immersed in an alkaline liquid of plant ash or a saturated aqueous solution of calcium hydroxide, etc., heat-treated to effect the green discoloration of the seaweeds and, as necessary, packed together with a 3W6% saline water or a seasoning liquid having the same order of osmotic pressure as that of the saline water. As an alternative method, raw seaweeds are immersed in an alkaline liquid of plant ash, washed with water, packed together with a saline water or a seasoning liquid, heat-treated in a hot water of 80W100°C and cooled, or seaweeds immersed in an alkaline water is washed with water, packed together with a saline water or a seasoning liquid heated at 80W100°C, and cooled. COPYRIGHT: (C)1989,JPO&Japio

Purification of saline water for ion exchange membrane electrolysis

Abstract: PURPOSE:To enable the removal of impurities in saline water stably over a long period to an extremely low level, by adding a caustic alkali or alkali metal carbonate to crude saturated saline water at a specific temperature and removing metallic ions with a chelate resin. CONSTITUTION:Crude saturated saline water containing magnesium ion, calcium ion and strontium ion as impurities is purified by the addition of a caustic alkali or an alkali metal carbonate. In the above process, the ratio of strontium concentration to calcium concentration in the refined saline water after the separation of precipitated impurities is maintained to =40 deg.C.

A Study on a Classification Technique of Natural Mineral Waters by Its Constitution and Physico-Chemical Properties

Abstract: Natural mineral water is generally quite different from ordinary drinking water due to its original nature and various properties. The complexity of natural mineral water requires, therefore, not only to identify its nature and proper characteristics, but also to classify them by a reasonable scientific basis of comparison. The study was concentrated on a possible classification technique to natural mineral waters by their constitutions and physico-ehemical properties. The classification was carried out by the computation of such numerical parameters as ionic equivalent percentage, electrolytic conductance or mobility, ionic molecular weight, molecular concentration, equivalent conductivity and degree of ionization in consideration of the determinative criteria as follows -particular single element or molecule -major components of natural waters as bicarbonate, sulphate, chloride, -total dissolved solids or salts (NaCl) The results obtained proved out to be clearly distinguhhable from ordinary drinking water as far as concern natural mineral water as an example on the subject -simple water -bicarbonate-predominating water -cold spring -carbonated-non gaseous water -weak alkaline water -non saline water Putting these various results together, the sample turned out to be a kind of natural mineral water that can be used as a drinking water if microbiologically safe. calcium, magnesium, and sodium -molecular concentration related to blood osmotic pressure -water temperature at emergence from spring -contents of free carbon dioxide (CO$_2$) -pH value of water

Effect of Saline Irrigation Water on Soil and Performance of Ber

Abstract: Salts accumulated in soils as a result of saline water irrigation (EC 2–7 to 9.0 ds m−1) of ber (Zizyphus miuritiana Lamk.) Cv ‘Gola’ grafted on boradi [Zizyphus nummularia (Burm. f.) Wight & Arn.; syn Z. rotundifolia] planted in microcatch-ment system were effectively leached by runoff and no significant carry over of salts was observed after the rainy season during seven years of study. Under flat bed plantation adequate leaching did not occur even when irrigated with waters of 2.7 ds m-1 EC. Irrigation waters of 2.7 to 9.0 ds m−1 were successfully used for establishment of ber plants. Fruit yield decreased by 10–20 per cent as a result of irrigation with waters of 9.0 ds m−1 EC. However, no adverse effect on fruit size was observed.

Observations of Saline Water Intrusion at Estuaries with Salt Wedges

Abstract: Longitudinal profiles of salt wedges were observed by ultrasonic means at the estuaries of the Shiribetsu, Mogami and Teshio River. The behavior of salt wedges and also the surface salinity distribution are greatly influenced by the shape of the river bed and the fluctuations of the river discharge. The changes of the bottom chiorinity and the movement of the interface level caused by the tide and the change of the river discharge were observed at the mouth of the Shiribetsu River from June to October, 1981 and 1982. The value of the bottom chlorinity increased from that of the fresh water to the sea water for several days in the middle of June after the flood season. The amplitude of the internal wave was 6.3 times as Iarge as the tidal motion of the surface.