scholarly journals Studi Distribusi Partikel Sedimen Tersuspensi Di Teluk Balikpapan Dengan Menggunakan Pemodelan Dispersal

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Fitri Suciaty ◽  
Putri Kemili ◽  
Tommy Harkey
Keyword(s):  
Suspended Sediment ◽  
Aquatic Ecosystems ◽  
River Estuary ◽  
Distribution Patterns ◽  
High Concentration ◽  
The West ◽  
Port Area ◽  
Sediment Particles ◽  
Hydrodynamic Factors ◽  
Mangrove Degradation

ABSTRAK Salah satu permasalahan penting sebagai akibat berbagai aktivitas di Teluk Balikpapan adalah erosi dan sedimentasi yang dapat menyebabkan degradasi lingkungan seperti peningkatan kekeruhan, pencemaran air, degradasi mangrove yang mengancam ekosistem perairan dan juga pendangkalan pada kawasan pelabuhan laut Balikpapan. Beberapa kajian erosi dan sedimentasi terdahulu di DAS Teluk Balikpapan menyatakan kandungan sedimen tersuspensi yang tinggi terdapat pada muara sungai-sungai utama yang bermuara ke Teluk Balikpapan. Pemodelan numerik hidrodinamika dan pemodelan dispersal dua dimensi untuk partikel sedimen tersuspensi dilakukan untuk memperoleh gambaran faktor-faktor hidrodinamika yang berpengaruh dan juga identifikasi pola distribusi partikel sedimen tersuspensi di Teluk Balikpapan. Simulasi sebaran partikel sedimen tersuspensi dilakukan pada beberapa skenario sumber partikel, yaitu di muara Sungai Semoi, hulu dan muara Sungai Riko, muara Sungai Wein, dan di bagian mulut Teluk Balikpapan. Simulasi dilakukan selama 15 hari untuk musim barat dan musim timur untuk mengetahui variasi sebarannya terhadap kondisi musim. Kata kunci: partikel sedimen tersuspensi, hidrodinamika, pemodelan dispersal, transpor sedimen. ABSTRACT One of the important problems as a result of various activities in Balikpapan Bay is erosion and sedimentation which can cause environmental degradation such as increased turbidity, water pollution, mangrove degradation which threatens aquatic ecosystems and also silting of the Balikpapan sea port area. Some previous erosion and sedimentation studies in the Balikpapan Bay watershed state that high concentration of suspended sediment is found in the estuaries of the main rivers that flow into Balikpapan Bay. Numerical hydrodynamic modeling and two-dimensional dispersal modeling for suspended sediment particles are carried out to obtain an overview of influential hydrodynamic factors and also to identify distribution patterns of suspended sediment particles in Balikpapan Bay. Simulations on the distribution of suspended sediment particles were carried out in a number of particle source scenarios, i.e. at the Semoi River estuary, upstream and Riko River estuary, Wein River estuary, and at the mouth of Balikpapan Bay. The simulation is carried out for 15 days for the west and east seasons to find out the seasonal variation. Keywords: suspended sediment particles, hydrodynamic, dispersal modeling, sediment transport.

scholarly journals Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

2021 ◽  
Author(s):  
David K. Ralston ◽  
Brian Yellen ◽  
Jonathan D. Woodruff
Keyword(s):  
Suspended Sediment ◽  
River Estuary ◽  
Dam Removal ◽  
Hudson River ◽  
Sediment Traps ◽  
Sediment Supply ◽  
Watershed Area ◽  
Natural Lakes ◽  
Sediment Deposits ◽  
Dam Removals

AbstractObservations and modeling are used to assess potential impacts of sediment releases due to dam removals on the Hudson River estuary. Watershed sediment loads are calculated based on sediment-discharge rating curves for gauges covering 80% of the watershed area. The annual average sediment load to the estuary is 1.2 Mt, of which about 0.6 Mt comes from side tributaries. Sediment yield varies inversely with watershed area, with regional trends that are consistent with substrate erodibility. Geophysical and sedimentological surveys in seven subwatersheds of the Lower Hudson were conducted to estimate the mass and composition of sediment trapped behind dams. Impoundments were classified as (1) active sediment traps, (2) run-of-river sites not actively trapping sediment, and (3) dammed natural lakes and spring-fed ponds. Based on this categorization and impoundment attributes from a dam inventory database, the total mass of impounded sediment in the Lower Hudson watershed is estimated as 4.9 ± 1.9 Mt. This represents about 4 years of annual watershed supply, which is small compared with some individual dam removals and is not practically available given current dam removal rates. More than half of dams impound drainage areas less than 1 km2, and play little role in downstream sediment supply. In modeling of a simulated dam removal, suspended sediment in the estuary increases modestly near the source during discharge events, but otherwise effects on suspended sediment are minimal. Fine-grained sediment deposits broadly along the estuary and coarser sediment deposits near the source, with transport distance inversely related to settling velocity.

scholarly journals A new Palaearctic species of the subgenus Lunatipula (Diptera, Tipulidae) from the West Caucasus with a survey of the caucasica species group

ZooKeys ◽  
2021 ◽  
Vol 1048 ◽  
pp. 145-175
Author(s):  
Vladimir I. Lantsov ◽  
Valentin E. Pilipenko
Keyword(s):  
New Species ◽  
Parallel Evolution ◽  
Distribution Patterns ◽  
Species Group ◽  
Palaearctic Species ◽  
The West ◽  
The Caucasus ◽  
Males And Females ◽  
First Time ◽  
Two Populations

The caucasica species group in the subgenus Lunatipula is redefined and now consists of five species native to the Caucasus. Tipula (L.) eleniyasp. nov. is described as new to science, and variations in the male terminalia in two populations are noted. Two subspecies (quadridentataquadridentata and quadridentatapaupera) are elevated to species rank. Detailed photo’s complement the descriptions of all five species (caucasica, eleniya, paupera, quadridentata, talyshensis), and data on ecology and distribution patterns are included as well as identification keys to males and females. Tipula caucasica is recorded from the West Caucasus and Tipula quadridentata is recorded from Dagestan (Russia) for the first time. Parallel evolution is traced in the male terminalia of the new species and in several non caucasica species group of Palaearctic Lunatipula.

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