Tidal Sea Research Articles

Optimum Dosage of Coagulant and Flocculant on Sea Water Purification Process

This study aims to determine the appropriate dose in the use of coagulant and flocculant, thereby make the use of chemicals This study used a design of experiment methods to determine the effect of treatment variation on water quality, ie coagulant and flocculant dose, raw material flow rate and sea water condition to turbidity and pH. As a reference, pH and turbidity must be below the maximum allowed for process water. The test was done in laboratory by using jar test method. The chemicals used as coagulants and flocculants was PAC polymers (poly amylum chloride). The results showed that coagulant and flocculant dose, flow rate and sea water condition had significant effect on turbidity and pH. The condition of seawater studied here is the tidal and low tide conditions. After variation of dosage and flow rate in sea tide and low tide conditions, the following conclusions were obtained; in tidal conditions, the optimum dose of coagulant and flocculant was 70 ppm at a flow rate of 450 m3 with reference turbidity 0.9 NTU and pH 6.9. While at low tide conditions, the optimum dose of coagulant and flocculant was 70 ppm at a flow rate of 420 m3 with reference turbidity 1.1 NTU and pH 6.9. This result is expected to be applied to factories that use seawater as raw material for process water.

Syntaxonomy and ecological differentiation of the pioneer vegetation of Ukraine. 1. Classes: Cakiletea maritimae, Ammophiletea, Crithmo-Staticetea, Crypsietea aculeatae, Therosalicornietea

Pioneer plant communities grow on newly-formed ecotopes of coastal and partially continental areas, on patches that have dried after the surface water flooding. They are affected by sea tides, wind-induced effect, salinity, denudation, accumulation and sharp changes in soil humidity. To these factors are added chemical and biological pollution, as well as anthropogenic pressure. Due to these reasons, such plant communities have a specific floristic composition, structure, functional regime and resilience mechanisms, which are different from coenoses of more stable habitats. On the basis of the analysis of more than 600 phytosociological relevés using TWINSPAN modified algorithm the current state of littoral and halophytic classes of pioneer vegetation in Ukraine has been established and their syntaxonomic structure identified. It has been determined that the level of pioneer phytocoenoses diversity in Ukraine is similar to that of Central Europe. The Cakiletea maritimae class is presented by 1 order, 1 alliance, and 4 associations; Ammophiletea – by 1 order, 1 alliance, and 8 associations; Crithmo-Staticetea – by 1 order, 2 alliances, and 3 associations; Crypsietea aculeatae – by 1 order, 3 alliances, and 4 associations, Therosalicornietea – by 1 order, 2 alliances, and 10 associations. Synoptic tables of vegetation classes are given and nine alliances are briefly characterized. Using DCA-ordination analysis of syntaxa in the association-rank level we identified that the main factors of ecological differentiation are soil humidity and aeration as well as the nitrogen content. For the pioneer plant communities, other significant impact factors are the extremality of environmental conditions, their unevenness and non-equilibrium, in particular, the mechanical action of the sea waves, the dynamic processes of denudation and accumulation, salinity, as well as the variability of damping during the year. This research contributes to the identification of the place of the distinguished syntaxa of Ukrainian pioneer vegetation in the European system.

Numerical modelling of the Caspian Sea tides

Abstract. The Caspian Sea is the largest enclosed basin on Earth and a unique subject for the analysis of tidal dynamics. Tides in the basin are produced directly by the tide-generating forces. Using the Princeton Ocean Model (POM), we examine details of the spatial and temporal features of the tidal dynamics in the Caspian Sea. We present tidal charts of the amplitudes and phase lags of the major tidal constituents, together with maps of the form factor, tidal range, and tidal current speed. Semi-diurnal tides in the Caspian Sea are determined by a Taylor amphidromic system with anticlockwise rotation. The largest M2 amplitude is 6 cm and is located in Türkmen Aylagy (called Turkmen Bay hereafter). For the diurnal constituents, the Absheron Peninsula separates two individual amphidromes with anticlockwise rotation in the north and in the south. The maximum K1 amplitudes (up to 0.7–0.8 cm) are located in (1) the south-eastern part of the basin, (2) Türkmenbaşy Gulf, (3) Mangyshlak Bay; and (4) Kizlyar Bay. As a result, the semi-diurnal tides prevail over diurnal tides in the Caspian Sea. The maximum tidal range, of up to 21 cm, has been found in Turkmen Bay. The strongest tidal currents have been located in the straits to the north and south of Ogurja Ada, where speeds reach 22 and 19 cm s−1, respectively. Numerical simulations of the tides using different mean sea levels (within a range of 5 m) indicate that spatial features of the Caspian Sea tides are strongly sensitive to changes in mean sea level.

Seiches in the Semiclosed Seas of the Continental Shelf

Seiche movements in two small areas of semi-closed seas on the Continental Shelf (the White Sea and the Sea of Azov) with very different morphometric characteristics are considered in this paper. In addition, tidal movements are highly developed in the White sea, while in the Azov sea tides are virtually absent. We’ve used morphometric characteristics of the seas, including the ones recently obtained by the Azov Sea, as well as methods of numerical hydrodynamic simulation based on the theory of shallow water, and spectral analysis of the observation data of the sea level fluctuations.

Membangun Kelompok Mahasiswa Peduli Lingkungan Melalui Penanaman Mangrove Pencegah Banjir Rob Jakarta

The purpose of community service activities is to provide knowledge and direct experience to students about the effects of tidal floods and improve the environment affected by tidal flooding through mangrove or mangrove replanting activities on vacant land around the coast or coastline. The method used is field recovery and community service where the activity is divided into several activities, including: a. the introduction of mangroves and how they are planted and how they grow and develop. b. presentation of material about tides or tides in the Jakarta sea that entered the Jakarta coastline area, the impact and problems if open land around the coast is gone. c. open land planting activities around Pantai Indah Kapuk-Muara Angke, North Jakarta. The results of the activities are a. Presentation of Material Regarding Mangrove Plants and Jakarta Sea Tides. b. mangrove planting in open fields. Summary of activities are a. that mangrove land in the Jakarta area, especially in the Pantai Indah Kapuk-Muara Angke region, North Jakarta has experienced a narrowing which resulted in the area of catchment and retaining sea tides or Jakarta has experienced a slight function. b. With the existence of field recovery activities and community service, students are expected to get direct experience and be able to solve problems that occur in the surrounding environment. c. The function of mangrove land is very important for the preservation and diversity of swamps or mangrove land.Keywords: Mangrove Plants; Rob Jakarta; Environmental Concern.

Energy-Aware Scalable Reliable and Void-Hole Mitigation Routing for Sparsely Deployed Underwater Acoustic Networks

In wireless underwater sensor networks (WUSNs), network protocols for information routing are usually designed when a significant number of nodes are present in the network. Therefore, for sparse conditions, when a noticeable reduction in the number of nodes occurs, the performance of such protocols exhibits a degraded behavior pattern. To cope with routing issues when sparse conditions prevail, two routing algorithms for WUSNs are proposed in this paper. They are energy-aware scalable reliable and void-hole mitigation routing (ESRVR) and cooperative energy-aware scalable reliable and void-hole mitigation routing (Co-ESRVR). The ESRVR uses a number of strategies. Firstly, it uses two hop neighbors’ information to develop routing trajectories for information advancement, as one hop information cannot avoid a void-hole, a condition when a node is not able to find neighbors towards the sea surface, and more than two hop information is difficult to obtain when sparse conditions prevail. Secondly, when a void-hole still exists, the protocol uses a backward transmission mechanism to find other routing paths to deliver packets to the end target. Thirdly, the time by which a packet is held by a node prior to transmission is short for the nodes with low energy, depth and high count of neighbors. This reduces packets loss and avoids congestion of the channel. It also helps the nodes with no or few neighbors to hold the packet for a significant chunk of time until they find suitable neighbors, due to sea tides and currents, for further packets’ advancement. The Co-ESRVR further adds reliability to information advancement by adding routing in a cooperative fashion to ESRVR, which involves packets advancement to destination along two paths: directly from source and via a relayed path. This provides multiple paths for data advancement to the sea surface, so that if one path is badly affected by the harsh sea characteristics, others may not be. Unlike the counterpart protocol, the proposed algorithms are not dependent on a node’s geographical location or the distance from the sea surface, which increases their scalability and reduces the computational complexity. Performance analysis displays superior behavior patterns of the proposed algorithms over the counterpart in terms of the compared characteristics.

Research on GPS precise point positioning algorithm with a Sea Surface Height Constraint

Marine surveying does not receive full benefits from RTK because there are lack of near reference stations along the coastal lines. Compared with RTK, PPP can realize positioning with just a single station, which can allow a wider operation range in marine applications, but its elevation positioning accuracy is significantly lower than the horizontal direction. For some ships with relatively static offshore operations, the vertical movement of ships is mainly affected by the tide, and the fluctuation of tide can be obtained by global tide models, etc. Therefore, we propose a GPS PPP method with a sea surface geodetic height constraint to make full use of sea tide motion information to improve PPP effect. In this paper, we establish the Sea Surface Height constraint PPP (SHC-PPP) model. It is noted that the GPS height is relative to WGS-84 reference ellipsoid, thus we convert the tide fluctuation information to the sea surface height relative to WGS-84 reference ellipsoid by adding a fixed value, which is the geodetic height of GPS receiver at the first epoch obtained in advance by using the post-positioning PPP minus the corresponding epoch's water level data predicted by FES2014. Validated by kinematic experiments, our SHC-PPP method can improve the vertical positioning accuracy over conventional PPP (PPPC) by 79%.

An operational forecasting system for physical processes in the Santos-Sao Vicente-Bertioga Estuarine System, Southeast Brazil

We describe the design, implementation, and performance of a fully automated Santos Operational Forecasting System (SOFS), built to monitor and predict short-term (< 3 days) sea surface elevations, currents, temperature, and salinity in the Santos-Sao Vicente-Bertioga Estuarine System (SSVBES). The SSVBES located at 24.0∘S, 46.3∘W is a complex estuarine system with many interconnected channels and two connections with the open sea. The system is prone to storm tides that bring coastal flooding to and interrupt ship traffic through Santos Port. The SOFS hydrodynamic module is based on the Princeton Ocean Model (POM) version POM-rain. The SSVBES model grid is forced by tides, winds, and river runoff and is nested into a coarse-resolution South Brazil Bight (SBB) grid. The SBB grid is forced by winds, density gradients, and the Brazil Current flowing offshore. Within SSVBES, SOFS works in parallel with three real-time observation stations. The model performance was tested against observed data with a best Willmott skill of 0.97 and root mean square error (RMSE) of 13.0 cm for tidal sea level (15.9% of the mean tidal range). For tidal currents, the best skill and RMSE were above 0.99 and 3.9 cm/s (4.3% of the mean tidal current range), respectively. The coupled system was able to simulate seven storm tides with average skill of 0.95 and average RMSE of 17.0 cm. The good agreement with observed data shows the potential use of the designed system to protect both human life and assets.

Numerical study of tides in the Bay of Sabang

This study aims to observe tidal sea behavior in Bay of Sabang by using a two-dimensional hydrodynamic model. The research domain was obtained from SRTM15, which had been interpolated so that it has a spatial resolution Δx = Δy = 0.1 minutes (185 meters). As a generator force, the open boundaries model is given five main tidal components (M2, S2, K1, N2, O1) obtained from TPXO 7.2 data. The model is simulated for 31 days with time step based on CFL condition criteria. Our model verification is quite good when compared with TMD prediction data (r = 0.9996). It shows that our model can be used for tidal hydrodynamics studies in Bay of Sabang. The results show that tides in Bay of Sabang are predominantly mixed prevailing semi-diurnal (F = 0.857). The speed of tidal currents in Bay of Sabang is quite small both for spring and neap tides. The difference in velocity between spring and neap tides reaches 0.6 cm/s.

Future Response of the Wadden Sea Tidal Basins to Relative Sea-Level rise—An Aggregated Modelling Approach

Climate change, and especially the associated acceleration of sea-level rise, forms a serious threat to the Wadden Sea. The Wadden Sea contains the world’s largest coherent intertidal flat area and it is known that these flats can drown when the rate of sea-level rise exceeds a critical limit. As a result, the intertidal flats would then be permanently inundated, seriously affecting the ecological functioning of the system. The determination of this critical limit and the modelling of the transient process of how a tidal basin responds to accelerated sea-level rise is of critical importance. In this contribution we revisit the modelling of the response of the Wadden Sea tidal basins to sea-level rise using a basin scale morphological model (aggregated scale morphological interaction between tidal basin and adjacent coast, ASMITA). Analysis using this aggregated scale model shows that the critical rate of sea-level rise is not merely influenced by the morphological equilibrium and the morphological time scale, but also depends on the grain size distribution of sediment in the tidal inlet system. As sea-level rises, there is a lag in the morphological response, which means that the basin will be deeper than the systems morphological equilibrium. However, so long as the rate of sea-level rise is constant and below a critical limit, this offset becomes constant and a dynamic equilibrium is established. This equilibrium deviation as well as the time needed to achieve the dynamic equilibrium increase non-linearly with increasing rates of sea-level rise. As a result, the response of a tidal basin to relatively fast sea-level rise is similar, no matter if the sea-level rise rate is just below, equal or above the critical limit. A tidal basin will experience a long process of ‘drowning’ when sea-level rise rate exceeds about 80% of the critical limit. The insights from the present study can be used to improve morphodynamic modelling of tidal basin response to accelerating sea-level rise and are useful for sustainable management of tidal inlet systems.

Predictability of non-phase-locked baroclinic tides in the Caribbean Sea

Abstract. The predictability of the sea surface height expression of baroclinic tides is examined with 96 h forecasts produced by the AMSEAS operational forecast model during 2013–2014. The phase-locked tide, both barotropic and baroclinic, is identified by harmonic analysis of the 2-year record and found to agree well with observations from tide gauges and satellite altimetry within the Caribbean Sea. The non-phase-locked baroclinic tide, which is created by time-variable mesoscale stratification and currents, may be identified from residual sea level anomalies (SLAs) near the tidal frequencies. The predictability of the non-phase-locked tide is assessed by measuring the difference between a forecast – centered at T+36, T+60, or T+84 h – and the model's later verifying analysis for the same time. Within the Caribbean Sea, where a baroclinic tidal sea level range of ±5 cm is typical, the forecast error for the non-phase-locked tidal SLA is correlated with the forecast error for the subtidal (mesoscale) SLA. Root mean square values of the former range from 0.5 to 2 cm, while the latter ranges from 1 to 6 cm, for a typical 84 h forecast. The spatial and temporal variability of the forecast error is related to the dynamical origins of the non-phase-locked tide and is briefly surveyed within the model.

Performances immersed in or interacted with unique environmental contexts

By selecting the 100 soundscapes in 1996 and coordinating follow-up events in 2002, the Ministry of the Environment, Japan drew the attention to rediscover and preserve unique sounds across the country. The diverse soundcapes are associated with wildlife, natural phenomena, or man-made sounds from industrial or cultural activities. In addition to appreciating the sound events, performances at outdoor Noh stages in Japan were immersed in unique environmental context historically. Bird chirping, wind blowing, and sea tide may all become the context of the play. Similar situation could be found for historical plays of Chinese operas at the stage integrated with a Chinese garden. There are modern facilities or events designed to immersed in or interacted with natural or man-made context. Some take advantage of unique acoustic effect such as echoes in valleys while the others create focus by isolating ambient disturbances and integrating soundscapes with visual, functional, or other forms of environmental qualities.

KEANEKARAGAMAN JENIS SEMUT (Formicidae) ARBOREAL DI HUTAN MANGROVE KELURAHAN SETAPUK BESAR KOTA SINGKAWANG

Arboreal ants are ants that do activities and spend their lives in tree. Roles of this organism are to serve as decomposers, pollinators, predators and indicators. Ant species diversity constitutes a chain for ecosystem stability. They are responsible as decomposing insects making their presence becomes ecologically vital. Research on ant species diversity in mangrove forest remains insufficient. One of the reasons possibly is that fact that mangrove is an ecosystem which is affected by sea tide. This research aims at gathering data about ant species diversity based on types of mangrove forest vegetation located in Setapuk Besar, Singkawang City. The research used a survey method by observing types of trees whose diameter was 10 cm and above. Additionally, the tree should have a large number of ants. The data was collected through fly sheet trap set under, in the mid, and above the tidal level. Findings revealed 6 types of ants consisting 4 sub-families in 6 types of the trees i.e. Rhizopora mucronata, Avicennia lanata, Hibiscus tiliaceus, Terminalia capatta, Nypa fruticans, and Bruguiera cylindrical.. Based on the diversity index of those 6 types of trees, the divercity of arboreal ants spesies could be categorized low (H’&lt;1). The highest diversity was nypa fruticans vegetation by 0.325. This was because the tree contains sugar level and carbohydrate. The lowest diversity was Hibiscus tiliaceus and Termialia catappa. The H’ value was 0. One of the reasons was because only one species of ants can be found in both trees, namely Oecophylla smaragdina.Keywords: Arboreal Ants, Diversity, Mangrove, Singkawang

ANALISA HARMONIK PASANG SURUT DENGAN METODE ADMIRALTY PADA STASIUN BERJARAK KURANG DARI 50 KM

Pasang surut laut merupakan sebuah fenomena naik dan turunnya permukaan air laut di bumi akibat pengaruh gravitasi benda luar angkasa, terutama matahari dan bulan. Pengamatan pasang surut laut sangat penting dalam penentuan referensi vertikal, untuk menyatukan data-data pengukuran di laut dan di daratan agar dapat diterjemahkan dalam satu kesatuan sistem pemetaan. Indonesia sebagai negara kepulauan terbesar di dunia yang memiliki luas laut 3,25 juta km2 dari 7,81 juta km2 total luas wilayah Indonesia, sudah seharusnya memiliki stasiun pasang surut yang tersebar merata di seluruh Indonesia. Penempatan stasiun tersebut juga harus tepat lokasi karena setiap perairan memiliki karateristik tersendiri. Badan Informasi Geospasial (BIG) mengelola 138 stasiun pasang surut (pasut) yang terdistribusi di seluruh wilayah Indonesia. Stasiun pasut tersebut pada umumnya ditempatkan di dermaga/pelabuhan, sehingga jarak antar staisun pasang surut menyesuaikan ketersediaan dermaga yang ada. Pada penelitian ini dilakukan analisa harmonik pasut dengan metode admiralty pada stasiun pasut BIG yang jarak antar stasiunnya kurang dari 50 km, disumsikan tipe pasut di lokasi yang berdekatan tersebut sama. Lokasi penelitian adalah stasiun pasut Ulee Lhue dibandingkan dengan stasiun pasut Malahayati, stasiun pasut Pel. Ciwandan dibandingkan dengan stasiun pasut Serang, stasiun pasut Sunda Kelapa dibandingkan dengan Pondok Dayung, dan stasiun pasut Pameungpeuk dibandingkan dengan stasiun pasut Pamayangsari. Hasil penelitian menunjukkan bahwa tipe pasut dilokasi yang dibandingkan tersebut memiliki karakteristik yang sama.

CONSIDERATION OF THE VALIDITY OF THE STATISTICAL CHARACTERISTICS OF pH IN SURFACE WATERS

Abstract: pH is one of the most important parameters characterizing the state of water systems. The arithmetic mean values of samples are often used when averaging serial pH measurements in water bodies, as is usually done for other characteristics of the state of the natural environment (temperature, salinity, oxygen concentrations, suspended solids, etc.). However, in this case such an operation is illegal, since the addition of logarithms, which by definition are pH, is non-additive. The authors conducted a study to determine the extent to which pH variability in natural objects such an operation would not distort the results. For this, several samples of the pH index were generated in various ranges of its theoretically possible and natural variability. It was established that with pH variability of less than a unit characteristic of marine pH values, the statistical characteristics of the indicator and [H+ ] concentrations differ slightly, and the medians of the samples coincide. It is concluded that with such ranges characteristic of the waters of the oceans, there is no need to recalculate previously obtained results. However, for the estuaries of rivers flowing into tidal seas, as shown by field measurements, the pH variability in the mixing zone of sea and river waters is several times higher. Similar situations may occur when heavy precipitation falls on the water surface, as well as during floods. In these cases, a simple averaging of the pH values will no longer be correct. In such cases, the use of other averaging algorithms and the choice of stable statistical characteristics are required.

Toward Realistic Nonstationarity of Semidiurnal Baroclinic Tides in a Hydrodynamic Model

AbstractSemidiurnal baroclinic tide sea surface height (SSH) variance and semidiurnal nonstationary variance fraction (SNVF) are compared between a hydrodynamic model and altimetry for the low‐ to middle‐latitude global ocean. Tidal frequencies are aliased by ∼10‐day altimeter sampling, which makes it impossible to unambiguously identify nonstationary tidal signals from the observations. In order to better understand altimeter sampling artifacts, the model was analyzed using its native hourly outputs and by subsampling it in the same manner as altimeters. Different estimates of the semidiurnal nonstationary and total SSH variance are obtained with the model depending on whether they are identified in the frequency domain or wavenumber domain and depending on the temporal sampling of the model output. Five sources of ambiguity in the interpretation of the altimetry are identified and briefly discussed. When the model and altimetry are analyzed in the same manner, they display qualitatively similar spatial patterns of semidiurnal baroclinic tides. The SNVF typically correlates above 80% at all latitudes between the different analysis methods and above 60% between the model and altimetry. The choice of analysis methodology was found to have a profound effect on estimates of the semidiurnal baroclinic SSH variance with the wavenumber domain methodology underestimating the semidiurnal nonstationary and total SSH variances by 68% and 66%, respectively. These results produce a SNVF estimate from altimetry that is biased low by a factor of 0.92. This bias is primarily a consequence of the ambiguity in the separation of tidal and mesoscale signals in the wavenumber domain.

The Dynamics of Sea Tide-Induced Fluctuations of Groundwater Level and Freshwater-Saltwater Interface in Coastal Aquifers: Laboratory Experiments and Numerical Modeling

Laboratory experiments were conducted in a vertical, two-dimensional, rectangular flow tank, simulating the response of a phreatic coastal aquifer to a sea tide. Imposed sinusoidal fluctuations of the saltwater level at one side of the flow tank caused three types of fluctuations: (a) hydraulic head throughout the aquifer, (b) saturation degree within the capillary fringe, and (c) salt concentration surrounding the freshwater-saltwater interface (FSI), all recorded by head, saturation, and salinity sensors, respectively. Significant time lags were observed both in the saturation degree within the unsaturated zone and in the salinity within the FSI. All measured values, recorded by the three types of sensors, were simulated and reproduced using a numerical model. The calibrated model was used for mapping the time lags throughout the aquifer. It was found that the time lag of saturation fluctuations within the unsaturated zone increased upward from the groundwater level as the unsaturated hydraulic conductivity decreased. Similarly, the time lag of salinity fluctuations within the FSI increased downward, with distance from the groundwater level. We interpret the low hydraulic conductivity at the capillary zone as the source of attenuation of both saturation and salinity, because both are controlled by the vertical advection of the whole freshwater body. This advection is significantly slower compared to the dynamics of pressure diffusion. The uniqueness of this study is that it provides quantitative data on the attenuation at the capillary zone and its effect on the salinity time lag in coastal aquifer systems.

Analysis Study Effect Of Surabaya's Northern Sea Tides On The Highway Drainage Channels (Case Study: Kedung Mangu Road, Sidotopo Wetan, Kenjeran, Surabaya)

One of the roads that is still a subscription to flooding in Surabaya when it rains is on Kedung Mangu road. Besides being close to the northern coast of Surabaya, Kedung Mangu road channel edge is still very small and a lot of trash and sediment. In this study the authors used secondary Gumbel method using the data from relevant agencies and secondary of data from observations in the field. Reviews These rainfall of data include the data, the data pool of the data the tide and the dimensions of the existing channels and other auxiliary buildings. From the data and the calculation, the value of the average rainfall is 93.41 mm / day. Rainfall intensity 25-year period is 47.949 mm / hour. While the flood discharge plan is 174.859 m3 / h. Its existing discharge chute is 100 908 m3 / h. From the Data Obtained tide high tide value of 150 cm occurred on December 13, 2016 and to its Lowest ebb -130 cm occurred on January 25, 2016. Thet Type of Surabaya's northern sea tides is the mixed tide. From the calculation and analysis can be concluded that the more influential is the amount of rainfall and dimensions and road conditions in the channel Kedung Mangu. So as to cope with floods In These locations, the dimensions of the channel should be enlarged.

Analytical Solution of Tidal Loading Effect in a Submarine Leaky Confined Aquifer System

Although there are many existing analytical studies of tidal groundwater level fluctuations in coastal aquifer systems, few of them focus on an offshore submarine aquifer. Here, we consider tidal groundwater head fluctuations in a submarine leaky confined aquifer overlain by a semipermeable seabed. Both the seabed and the confined aquifer are assumed to extend horizontally infinitely. A one-dimensional mathematical model is established to describe the problem, and the analytical solution is derived. The impacts of the tidal loading efficiency, hydraulic conductivity and elastic storage of the semipermeable layer and aquifer on the groundwater head fluctuations in the aquifer system are analyzed and discussed. Solution analyses indicated that tidal loading effects tend to enhance the amplitude of the tidal groundwater fluctuation in the confined aquifer system and to reduce the phase shift between the groundwater head and the sea tide fluctuations.

Environmental Impact Assessment of the Tidal Link Failure and Sea Intrusion on Ramsar Site No. 1069

This paper presents the impact on the RAMSAR site No. 1069 that receives fresh water by the Kotri drainage system. At present, the complex faces threats by effluents from the Left Bank Outfall Drain (LBOD) system and from saline seawater intrusion during high tides. These threats have destroyed the ecosystem of the lakes Cholari, Mehro, Pateji and Sanhro belonging to the complex. The total present lake area, maintained at the Cholari weir crest level, is about 170km2. The lakes are expanding, available data shows that there is an increase up to 700% in the original lakes’ area, from 6058 to 41220 acres from 1954 to 1977. This is mainly caused by the operation of Kotri Barrage surface drainage system and has positive impact on lakes’ ecology because the drainage effluent is of marginal salinity. The rapid increase in the lakes’ area, of about 40% within 2 years after the functioning of the Tidal Link with saline effluents from LBOD and sea intruded water have changed the ecology of the area. This posed a significant impact on the ecosystem. Conversely, a similar rise in water level due to sea intrusion has nearly doubled the surface area and reposed a negative impact on the system. These lakes were giving shelter to a wide variety of local and migratory birds and had aquatic biodiversity. Hence, parts of Sanhro and Mehro dhands have been recognized by the RAMSAR Convention