How to Measure the Coastal Currents of Porthcawl

1. Where is Porthcawl?

Porthcawl is a quaint seaside town in Bridgend County Borough, Wales, on the southern shore on the Bristol Channel. Its geographic location has developed an age - old and deep - seated association with the sea that has made profound marks on its development, economy, and life of the inhabitants.

Porthcawl has a rich history. It has expanded from a tiny fishing village to a popular seaside resort. The town architecture is a combination of traditional Welsh and modern styles. There are old - fashioned stone - built houses with typical characteristics in the town center. The houses have thick, solid walls, small - framed windows, and slate - tiled roofs, with an unmistakable Welsh coastal feel. The seafront itself has modern promenades, amusement arcades, and hotels to cater to the large number of tourists who visit throughout the year. There are modern shops, cafes, and restaurants along the main roads, catering to the local population as well as tourists.

The people of Porthcawl have a strong connection with the sea. Fishing has been a tradition passed down through generations. While the fishing industry has been altered over the years, there are still a few local fishermen who sail out from the harbor. They come back with catches such as mackerel, herring, and other shellfish. The harbor is not just a spot for fishing but also a bustling spot for boat tours by locals and tourists. Members of the public may enjoy the sea breeze, seabirds in flight overhead, and the pretty view of the Bristol Channel.

The seashore and sea around Porthcawl are of critical significance to the environment. The sea of the Bristol Channel at this location boasts an extensive diversity of sea animals. Seals may often be seen on the sandbanks, while seabirds such as gulls, terns, and cormorants may be seen regularly. The seabed is extremely irregular in itself, having sandy areas, patchy outcrops of rock, and underwater channels. These are all of high biodiversity and play an important part in the flow of the water.

2. What is the State of the Coastal Currents off Porthcawl?

The coastal currents off Porthcawl are governed by a number of factors. One of the big ones is tidal pressures. The Bristol Channel has semi-diurnal tides with a relatively large tidal range. The tidal currents generated by them can be as much as 3 - 4 knots in some areas, especially at the entrances of small inlets or headlands. During high tide, water rushes towards the coast, bringing with it nutrients and sediment from the open sea. This enhances the local sea environment, supporting habitats and the food supply of a variety of sea life. At low tide, the water recedes, uncovering intertidal pools and exposing little crabs, sea anemones, and other seaweed species.

Wind is the second factor of significance. Dominant south - westerly winds have a tendency to drive surface waters onto the coast, causing the coastal currents to be more powerful. These winds also generate waves which interact with the currents to generate a more complex flow pattern. Northerly winds can force the water off the shore. The headlands, bays, and unique features of the south - Welsh coast shape cause the currents to converge and diverge in different areas. Rocky outcrops underwater and sandbars contribute to the complexity of the current patterns. These can act as barriers or conduits, deflecting the water flow and creating areas of still or turbulent water. Furthermore, the entry of freshwater from small local streams can affect the local current patterns. The freshwater, being less dense than seawater, floats on the surface and flows towards the sea, blending with the tidal and wind - driven currents.

3. How to Measure the Coastal Water Current of Porthcawl?

Surface Drifting Buoy Method

Surface drifting buoys are a good method for measuring surface - level currents off Porthcawl. They have GPS or satellite - based tracking equipment on board. Once deployed, they float at the mercy of the surface currents. Scientists monitor their progress over time. With readings of the motion of the buoy, they're able to determine the speed and direction of surface waters. The method, however, has limits in only the upper few meters of the water column. It might not necessarily be representative at all of what's happening out in the water's deeper areas, where flows could be varied depending on things like temperature and salinity change.

In the moored ship technique, a ship is moored at a location near the Porthcawl coast. Then current-measuring equipment like electromagnetic current meters are dropped. The equipment is able to sample the water flow at multiple depths. The equipment provides a true vertical profile of the speed and direction of the current. But this process is confined to one location. In addition, the presence of the ship can have the potential to interfere with the natural water flow. The ship's hull and way of mooring are capable of creating turbulence in the water, which might affect measurement accuracy.

Acoustic Doppler Current Profiler (ADCP) Method

It has become possible to measure coastal currents off Porthcawl due to ADCPs. ADCPs can measure the whole velocity profile of the water column from bed to surface. ADCPs utilize the application of sound waves to non-destructively establish the water flow. They release acoustic pulses and measure the Doppler shift of the backscattered signals off suspended particles within the water, for example, sediment, plankton, or small bubbles. On this basis, they can establish the current velocity at different depths. This creates a full overview of the prevailing configuration, making it highly applicable for studying the complex coastal current dynamics in Porthcawl.

4. What Does It Take to Achieve High-Quality Measurement of Porthcawl Coastal Currents?

Equipment Material Reliability

In order to measure the coastal currents off Porthcawl at high quality, equipment material reliability is highly critical. The ADCP flow meter casing should be made of a material that is robust enough to withstand the aggressive marine environment of the Bristol Channel. Titanium alloy is a suitable choice. Its high strength allows it to resist the pressure of powerful currents of water, potential impacts from floating debris, and corrosiveness of seawater. Its low elastic modulus provides it with flexibility so that it cannot be easily broken by mechanical stress. Also, its superior corrosion resistance allows the ADCP current profiler to be left in the water for long-term monitoring without much degradation.

Small Size, Light Weight, Low Power, and Low Cost

It is easier to install and operate a light weight and small ADCP profiler. You may install it on a small research vessel, hang it from a buoy, or put it on the seafloor. It also disturbs the natural flow of water to a lesser extent, which results in more accurate measurements. Low power is required for long - term self - sustaining surveillance, especially using battery - powered systems. Mass deployment is supported by a low-cost ADCP. This must be equipped with a thorough understanding of the intricate patterns of currents along the Porthcawl coast. As more ADCPs are deployed at other points, we are able to understand more about the variations in currents across the area.

5. Selection of Appropriate Equipment for Measurement of Current?

Usage-based

• Shipborne ADCP: Ideal for obtaining current data in real time along the track of a passing vessel near Porthcawl. It can be utilized to carry out oceanography surveys, studies on the regional general circulation, and routing optimization, if any, of shipping in the area.
• Bottom-mounted ADCP: Best for long - term, fixed - point measurements of the seabed currents. This is useful in monitoring the long - term trends of the coastal currents, e.g., the effects of climate change on the marine ecosystem of the locality.
• Buoy-mounted ADCP: Ideal for monitoring surface - level currents over a wide area since the buoy is transported with the water. It helps in understanding the spatial variation of the surface currents and the way coastal waters exchange with the open Bristol Channel.

Based on Water Depth

• 600kHz ADCP: Well-suited for water depths to approximately 70m, and taking high-resolution measurements in reasonably shallow waters nearer Porthcawl.
• 300kHz ADCP: Well-suited for water depths of approximately 110m, and possibly ideally suited for those places with some deeper areas in the Bristol Channel nearer town.
• 75kHz ADCP: Intended for deep-water uses. Although waters around Porthcawl tend to be usually not very deep, it may be utilized in the case of studies concerning deeper-layer currents or deeper-channel areas with the capability of measuring the current up to depths of 1000m.

Several established ADCP brands are available in the global market, such as Teledyne RDI, Nortek, and Sontek. For someone seeking a cost-effective option, the China Sonar PandaADCP, all-titanium alloy, is an excellent choice in terms of price-performance. You can learn more about it at (https://china-sonar.com/).

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