Simple estimate of filtration rates on a sandy beach

A new, simple and inexpensive method is proposed to determine the rate of water filtration in the swash zone of lakeshore beaches. Rates of water filtration on a sandy beach were determined by measuring the residue of a tracer injected into several cylinders buried vertically in the sandy layer at various locations from the shoreline to the tip of the swash zone. This methodology enabled the separate estimation of mean infiltration and exfiltration rates. The results obtained for seashore beaches were in accordance with previous data obtained by more conventional methods. The filtration rate results for lakeshore sandy beaches were almost equivalent to seashore sandy beaches, despite a shorter swash length. This paper indicates that this is caused by a larger grain size and shorter wave period. This method presents an easy approach to determine rates of water filtration in sandy beaches and is expected to further promote studies in this field.