How to Measure the St Andrews Coastal Currents

1. Where is St Andrews?

St Andrews is a beautiful seaside resort town in the county of Fife, Scotland. It is located on the east coast of Scotland, opposite the North Sea. This idyllic spot has given St Andrews a well-established and long - rooted affinity with the sea, which has influenced its past, economy, and lifestyle.

The town has a rich past which dates back over a thousand years. It is renowned for being the "Home of Golf" with the Old Course, one of the oldest and most renowned golf courses in the world. St Andrews also boasts a religious history with the remains of St Andrews Cathedral, reminding people of the past. The St Andrews architecture is a medieval and modern mix. The town center is made up of old stone - built houses with robust walls, small arched windows, and heavily pitched roofs. They have history and personality to them. Surrounding the coastal towns, there are present-day hotels, restaurants, and stores serving the numerous visitors who come to the town, particularly those arriving for golf, beach activities, or to sightsee the sites of historical importance.

The locals in St Andrews share a profound affinity with the ocean. Fishermen have made a long-time occupation of the town, albeit in reduced proportion with the passing of time. A handful of local fishermen still set out from the small harbour, coming back with their harvests of mackerel, herring, and a now-and-again lobster. Not only for the fishing boats is the harbour open, but it is also accessible to the general public and visitors to ride a boat. Anyone can enjoy the sea breeze, watch seabirds fly by, and feast their eyes on the horizon view of the North Sea.

The seas and beaches of St Andrews are important to the local ecosystem. The North Sea waters off St Andrews are home to a rich diversity of marine life. Seals are commonly seen on the sandbanks, and seabirds such as gulls, terns, and puffins are often observed. The seafloor is topographically diverse, with sandy areas, solitary rocky outcrops, and underwater channels. These properties allow for high biodiversity and play an important role in the movement of water.

2. What is the State of the Coastal Currents Off St Andrews?

The coastal currents off St Andrews are influenced by a number of factors. Tidal forces are among the most important. The North Sea has semi - diurnal tides, two high tides, and two low tides per day. The tidal range itself can vary, and the generated tidal currents can be up to 2 - 3 knots in some locations, especially around small inlet entrances or in distinct coastal geometry. During high tide, water is directed toward the coast, bringing with it the nutrients and sediments from the open ocean. It nourishes the surrounding marine environment, providing food and environments for an array of sea creatures. During low tide, the ocean recedes and the intertidal zones are exposed to small crabs, anemones, and other types of seaweed.

Wind is another crucial factor. South - westerly prevailing winds can push surface waters inshore, strengthening coastal currents. These winds also produce waves that influence the currents, creating a more complex flow regime. Northerly winds have the power to drive the water off shore. The bending of the coast, the presence of bays, headlands, and the peculiarities of the area lead to the convergence and divergence of the currents at different places. Rocky outcrops beneath the sea and sandbars complicate the patterns of the currents. They can be barriers or channels, deflecting the course of the water and creating areas with still or disturbed water. In addition, freshwater from the minor local rivers also affects the regional current patterns. The lighter freshwater forms the upper layer and is carried inshore towards the ocean, combining with the tidal as well as the wind-related current.

3. Observing St Andrews' Coastal Water Flow

Surface Drifting Buoy Method

Surface drifting buoys are a simple and effective way to track the surface - level currents in the vicinity of St Andrews. Surface drifting buoys are equipped with GPS or satellite - based tracking devices. After being released into water, the surface currents carry them along. Scientists can track their movement over time. By analyzing the trajectory of the buoy, scientists can estimate the speed and direction of the surface waters. However, this method is only used for the upper few meters of water column. It might not reflect what really happens in the bottom region of water, where the currents can be mixed according to factors such as temperature and salinity variations.

Moored Ship Method

A ship is anchored in a fixed location near St Andrews' coast with the moored ship method. Second, in-stream-measuring instruments like electromagnetic current meters are employed. They can measure the water current at different depths. They provide a precise vertical profile of the current velocity and direction of the current. Yet, this method is restricted to one location. Additionally, the presence of a ship has the potential to interrupt the natural water flow. The ship hull and the method of ship mooring can create turbulence within the water, which may affect the reliability of the measurements.

Acoustic Doppler Current Profiler (ADCP) Method

ADCPs have revolutionized coastal current measurement off St Andrews. ADCPs are able to monitor the velocity profile of the entire water column from the seafloor to the surface. ADCPs use sound waves in order to non - intrusively measure the flow of the water. They emit acoustic pulses and measure the Doppler shift of the back-scattered echoes from suspended particles in the water column, such as sediment, plankton, or fine bubbles. This allows them to calculate the speed of the currents at different levels. This gives a complete picture of the structure of the currents and is ideally suited to investigating the fine coastal current system off St Andrews.

4. What is Needed for High-Quality Measurement of St Andrews Coastal Currents?

Material Reliability of the Equipment

The equipment materials should be reliable to enable high-quality measurement of the coastal current off St Andrews. The ADCP current meter casing should be constructed with a material that will withstand the hostile marine environment off the North Sea. Titanium alloy is the optimal choice. Its high strength allows it to resist the pressure of high water currents, potential impacts by floating debris, and the corrosive nature of seawater. Its low elastic modulus makes it flexible, allowing it to withstand mechanical stress and damage. In addition, its high corrosion resistance allows the ADCP current profiler to be submerged in water for extended monitoring without serious deterioration.

Small Dimensions, Light, Low Power Draw, and Inexpensive

It is easier to install and operate a smaller and lighter ADCP meter. It can be attached to a research boat of smaller size, mounted on a buoy, or stationed on the bottom of the seafloor. It also places a lesser influence on the original water flow in nature, giving more accurate results. Low power usage is essential for independent monitoring over long periods, especially when employing battery - powered systems. Low-cost ADCP enables large-scale deployment. This is needed to achieve a thorough understanding of the complex coastal current patterns in the vicinity of St Andrews. Having more ADCPs in other areas, we can have a clearer idea of how the currents vary across the region.

5. Choice of Suitable Equipment for Current Measurement

Based on Application

• Shipborne ADCP: Most suitable to collect real-time current information along the path of a ship around St Andrews. It can be used for oceanographic surveys, studying the overall circulation around the region, and routing optimization, if any in the area.
• Bottom-mounted ADCP: Suitable for long - term, fixed - point measurement of the seabed current. This is applied in the study of coastal current long - term trends, for instance, how the local ocean environment is affected by climate change.
• Buoy-mounted ADCP: Suitable for the monitoring of surface - level currents over extensive regions since the buoy is transported by the water. It helps in understanding the spatial variability of the surface currents and the coastal water interaction with the open North Sea.

Based on Water Depth

• 600kHz ADCP: Ideal for waters of approximately 70m, enabling high resolution measurement in relatively shallow waters near St Andrews.
• 300kHz ADCP: More applicable to water depths of approximately 110m, which may be suitable in areas with slightly deeper pockets in the North Sea near the town.
• 75kHz ADCP: For use in deep water. While the waters along St Andrews are not usually particularly deep, it can be used for studies of the deeper-layer currents or for deeper channel regions, and it can record currents to 1000m depth.

There are several well-known ADCP brands in the global market, such as Teledyne RDI, Nortek, and Sontek. For those who prefer a budget-friendly option, the China Sonar PandaADCP, made of all - titanium alloy, is a great quality-to-price ratio. You can learn more about it at (https://china-sonar.com).

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