How to Measure the Coastal Currents of Swansea

1. Where is Swansea?

Swansea is a sizeable seashore city in Wales on the southern coast of the Bristol Channel. Its outstanding location has conferred upon it a long - term and extensive connection with the sea, which has been at the heart of its development, economy, and life of its people.

Swansea has a rich historical history. It has developed from a little fishing village into a significant commercial and industrial center. The history of the city is indissolubly tied with copper - smelting industry, export of coal, and then tourism development. Swansea architecture combines many styles. In the inner city, the buildings of Victorian times with their classic ornate facades, large windows, and ornamentations remain, attesting to the richness of the industrial age. Recent years also have seen newer modern skyscrapers and buildings spring up to inject a slice of modernism into the city. There are a variety of seafront attractions, such as the Swansea Marina, which is full of boats and yachts, and the National Waterfront Museum, which displays the maritime and industrial past of the city.

The people of Swansea have an historical connection to the sea. Fishing was also a major occupation in the past, and although its importance has reduced, the sea remains a major contributor to the local economy through tourism and marine services. The beaches are also frequented by locals and tourists, where swimming, sunbathing, and water sports are undertaken. The city also hosts various maritime - related events and festivals throughout the year, marking its association with the sea.

The seashores and sea waters near Swansea are important to the area. The marine waters of the Bristol Channel along here support a diverse range of marine species. Seals appear regularly in estuaries and along the shore, and seabirds including gulls, terns, and cormorants can be seen on a regular basis. The seafloor is extremely complicated with sandy areas, mudflats, and undersea channels. These features do not only favor rich biodiversity but also significantly impact the flow of the water.

2. What is the State of the Coastal Currents in Swansea?

Coastal currents in Swansea are governed by many factors. One of the outstanding factors is tidal forces. Bristol Channel possesses one of the greatest tidal ranges worldwide, and there are semi-diurnal tides there. The tidal flows thus created are highly strong, with speeds of up to 4 - 5 knots in some locations, especially near the narrow channels and around headlands. During high tide, water rushes towards the shore, bringing with it sediments and nutrients from the open sea. This makes the marine ecosystem locally rich, providing nourishment and habitat to other marine animals. When the tide recedes, water is lost and the intertidal mud and mudflats are uncovered, revealing a rich diversity of small invertebrates and diversity of species of seaweed.

Wind is another significant factor. Frequent south - westerly winds are capable of pushing surface waters on to the coast and strengthening the coastal currents. These winds also produce waves which can interact with the currents to make the flow pattern more complex. Northerly winds can force the water away from the shore. The topography of the Swansea coastline, the bays, headlands, and the typical features of the south - Welsh coast cause the currents to converge and diverge in many areas. Sandbars and outcrops beneath the water increase the complexity of current patterns. They could be barriers or channels, skirting the direction of water movement and creating areas of still or turbulent water. The freshwater that enters from the River Tawe and other smaller tributaries also affects local current patterns. The freshwater is less dense compared to seawater and rides upon it, and flows seawards, combining with the tidal and wind-forced currents.

3. Observation of Swansea's Coastal Water Flow

Surface Drifting Buoy Method

Surface drifting buoys are a suitable, low - cost technique for observing surface - level currents near Swansea. GPS or satellite - based tracking devices are attached to the buoys. Surface currents push them after they are released into the ocean. Scientists can trace their path over time. By watching the trajectory of the buoy, they can estimate the speed and direction of the surface water. This is only for the top section of a few meters of the water column, however. It might not be what's really happening in the depths of the water, where the currents are possibly changing because of changes in temperature and salinity.

Moored Ship Method

In the ship mooring method, a ship is moored at a single location near Swansea's coast. Then current-measuring instruments like electromagnetic current meters are dropped down. These meters can measure the water current at different depths. They provide a precise vertical profile of the current velocity and direction. But the method is restricted to a single location. Besides, the presence of the ship can potentially disrupt the natural movement of water. The shape of the ship's hull and its mooring can create ripples in the water, which affect the accuracy of the readings.

Acoustic Doppler Current Profiler (ADCP) Method

ADCPs have revolutionized the measurement of coastal currents along Swansea. They can measure the velocity profile of the whole water column from the surface to the bottom of the sea. ADCPs directly measure water flow by emitting sound waves. They emit acoustic pulses and measure the Doppler shift of backscattered signals from suspended objects in water, such as sediment, plankton, or tiny bubbles. They can then calculate the current velocity at different depths. This gives an overall impression of the current structure and therefore is extremely suitable for analysis of the intricate coastal current streams around Swansea.

4. What Is Required to Have High-Quality Measurement of Swansea Coastal Currents?

Equipment Material Reliability

To have high-quality measurement of the coastal currents off Swansea, equipment material reliability is necessary. The ADCP flow meter casing needs to be made of a material that can withstand the harsh marine environment of the Bristol Channel. Titanium alloy is well suited. Its high strength is capable of supporting the force of high water flows, potential bumping against buoyant objects, and the corrosive nature of sea water. Its low modulus of elasticity allows it to bend, reducing the chance of damage by mechanical stress. In addition, its very good corrosion resistance makes it feasible to submerge the ADCP profiler into the water for extended observation without losing efficiency significantly.

Low Cost, Compact Size, Lightweight, and Low Power Consumption

A light-weight, compact ADCP current profiler is easier to install and to operate. It can be installed on a small research ship, mounted on a buoy, or set on the seafloor. It is also less disturbing on the natural stream flow, with higher accuracy measurement. Low power consumption is essential for long-term independent monitoring, especially when utilizing battery - operated systems. Low-cost ADCP allows large-scale deployment. This is needed to completely grasp the complex coastal current patterns around Swansea. With more ADCPs deployed at different points, we can understand better how the currents vary across the region.

5. Selection of Appropriate Equipment for Current Measurement?

• Shipborne-ADCP: Ideal for collecting real-time current data along the route of a ship off Swansea. It could be used in oceanographic surveys, investigation of the general circulation of the region, and shipping route optimization, as Swansea remains an important port.
  
• Bottom-mounted ADCP: Can be used for long - term, fixed - point monitoring of seabed currents. This is useful for long - term study of coastal current trends, including the effect of climate change on the local ocean ecosystem.
  
• Buoy-mounted ADCP: Ideally for monitoring surface - level currents across a wide area since the buoy gets transported with the water. It helps in understanding the spatial variability of the surface currents and how the coastal waters communicate with the open Bristol Channel.

According to Water Depth

• 600kHz ADCP: Ideal for water depths of approximately 70m, providing high-resolution measurements in the comparatively shallow water near Swansea.
• 300kHz ADCP: Ideally suited to water depths of approximately 110m, which can be used for application in regions with a bit deeper sections in the Bristol Channel near the city.
• 75kHz ADCP: Good enough for deep-water applications. While the waters just off Swansea are not typically very deep, it can be used for investigations related to the deeper-layer flows or for areas that have deeper channels, with the capacity to measure flows up to 1000m deep.

Some of the major ADCP brands on the global market include Sontek, Nortek, and Teledyne RDI. Anyone looking to economize on an ADCP can try the China Sonar PandaADCP, which is made of all - titanium alloy for a great balance of price and quality. More information can be accessed at (https://china-sonar.com/).

Here is a table with some well known ADCP instrument brands and models.