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Figure 1. Location of the study area (A), the four beaches analysed in the Gulf of Cadiz and the wave buoy (B). Samples were taken from four beaches located in the Gulf of Cadiz: Santa Maria del Mar (SMM), Victoria (VB), Camposoto (CB), and La Barrosa (BB) (Figure 1). SMM has the particularity that it is embedded between two lateral groynes that confine it.

Figure 1 Location of the study area (A), the four beaches analysed in the Gulf of Cadiz and the wave buoy (B). Samples were taken from four beaches located in the Gulf of Cadiz: Santa Maria del Mar (SMM), Victoria (VB), Camposoto (CB), and La Barrosa (BB) (Figure 1). SMM has the particularity that it is embedded between two lateral groynes that confine it.

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Figure 2. Location of the profiles monitored in the four different beaches: SMM (A), Victoria (B), Camposoto (C), and Barrosa (D). A wind rose diagram (E) is also presented. The orientation of the beaches is approximately NNW in all of them. Figure 2. Location of the profiles monitored in the four different beaches: SMM (A), Victoria (B),
Figure 2. Location of the profiles monitored in the four different beaches: SMM (A), Victoria (B), Camposoto (C), and Barrosa (D). A wind rose diagram (E) is also presented. The orientation of the beaches is approximately NNW in all of them. Figure 2. Location of the profiles monitored in the four different beaches: SMM (A), Victoria (B),
ie, oad - For a proper comprehension, visual data of Hs, peak period (Tp), and wave direction are shown in Figure 3. Figure 3. Wave data during the monitoring time between March 2015 and June 2016: Hs (in meters, (top)), Tp (in seconds, (centre)), and wave direction (being 0° and 360° in the north, 90° in the east, 180° in the south, and 270° in the west, (bottom)). The survey dates used in the analysis are marked vertically. Source: own elaboration with data from the Spanish port administration www.puertos.es (15 August 2021). [80° in the south, and 270° in the west, (bottom)). The survey dates used in the analysis are marked
ie, oad - For a proper comprehension, visual data of Hs, peak period (Tp), and wave direction are shown in Figure 3. Figure 3. Wave data during the monitoring time between March 2015 and June 2016: Hs (in meters, (top)), Tp (in seconds, (centre)), and wave direction (being 0° and 360° in the north, 90° in the east, 180° in the south, and 270° in the west, (bottom)). The survey dates used in the analysis are marked vertically. Source: own elaboration with data from the Spanish port administration www.puertos.es (15 August 2021). [80° in the south, and 270° in the west, (bottom)). The survey dates used in the analysis are marked
Table 1. Dates of the monitoring campaigns when samples were taken. This analysis was carried out with samples taken from the SMM, Victoria, Camposoto, and Barrosa beaches during the 2015-2016 period. Dredging and beach nourishment works began and were finished in May-June 2015. A sampling of sand before nourishment, at the end of April, was performed to determine the natural configuration of every beach and, therefore, its native sand parameters. Afterward, three additional samplings of sand were performed semi-annually after the nourishment to monitor their evolution. Ds5g was measured in mm, while sorting was calculated in phi units, a logarithmic scale, following the research of Damveld et al. [36]. The dates of these four campaigns are shown in Table 1.
Table 1. Dates of the monitoring campaigns when samples were taken. This analysis was carried out with samples taken from the SMM, Victoria, Camposoto, and Barrosa beaches during the 2015-2016 period. Dredging and beach nourishment works began and were finished in May-June 2015. A sampling of sand before nourishment, at the end of April, was performed to determine the natural configuration of every beach and, therefore, its native sand parameters. Afterward, three additional samplings of sand were performed semi-annually after the nourishment to monitor their evolution. Ds5g was measured in mm, while sorting was calculated in phi units, a logarithmic scale, following the research of Damveld et al. [36]. The dates of these four campaigns are shown in Table 1.
Figure 4. Different levels surveyed in each beach profile. Sampling was carried out for four different levels in each transverse profile (Figure 4). The elevations of these levels were: —1 m (submerged), 0 m (the Lowest Low Water Level, LLWL or datum), 2 m (intertidal zone), and 4m (over Highest High Water Level, HHWL or dry beach).
Figure 4. Different levels surveyed in each beach profile. Sampling was carried out for four different levels in each transverse profile (Figure 4). The elevations of these levels were: —1 m (submerged), 0 m (the Lowest Low Water Level, LLWL or datum), 2 m (intertidal zone), and 4m (over Highest High Water Level, HHWL or dry beach).
A Van Veen grab can typically be used to collect submerged samples by throwing it into the sea at a depth of —1 m. Sand accumulates inside it, and the rope is later hoisted to lift the bucket. This procedure can also be done by hand if the conditions are favourable, ie., ata shallow depth (~1 m) and under slow-current conditions. In our case, samples were collected directly by hand, because fines tend to escape from the Van Veen grab.
A Van Veen grab can typically be used to collect submerged samples by throwing it into the sea at a depth of —1 m. Sand accumulates inside it, and the rope is later hoisted to lift the bucket. This procedure can also be done by hand if the conditions are favourable, ie., ata shallow depth (~1 m) and under slow-current conditions. In our case, samples were collected directly by hand, because fines tend to escape from the Van Veen grab.
Table 3. Total variation of Dso (between native sand and nourished sand after one year) at SMM, VB, CB, and BB at the different levels of the profile (Submerged, LLWL, Intertidal, and HHWL).
Table 3. Total variation of Dso (between native sand and nourished sand after one year) at SMM, VB, CB, and BB at the different levels of the profile (Submerged, LLWL, Intertidal, and HHWL).
Figure 6. Results of Ds9 (in mm) obtained at the four beaches (Santa Maria del Mar, Victoria, Camposoto, and Barrosa) during one year of monitoring. between 0.25 and 0.30 mm were maintained in all the analysis, with this being of vital importance for the stability of the beach. This larger size resulted from the larger grain size of the sand used for nourishment relative to the native sand (see the Dsg values reached just after nourishment in Table 2). For instance, we can see how the grain size of the native sand was less than that of the borrowed sand at SMM. The largest Ds) values within the nourished sand were found in the upper area of the beach, given that sand was dumped almost entirely in the upper area of the beach due to the pumping system, to reach a settling of the sand [43] as shown in Figure 7.
Figure 6. Results of Ds9 (in mm) obtained at the four beaches (Santa Maria del Mar, Victoria, Camposoto, and Barrosa) during one year of monitoring. between 0.25 and 0.30 mm were maintained in all the analysis, with this being of vital importance for the stability of the beach. This larger size resulted from the larger grain size of the sand used for nourishment relative to the native sand (see the Dsg values reached just after nourishment in Table 2). For instance, we can see how the grain size of the native sand was less than that of the borrowed sand at SMM. The largest Ds) values within the nourished sand were found in the upper area of the beach, given that sand was dumped almost entirely in the upper area of the beach due to the pumping system, to reach a settling of the sand [43] as shown in Figure 7.
Figure 7. Sand pumping system in a photo (A) and schematised diagram (B). The pipe is brought to the beach and placed within an artificial ridge. This pipe releases a mixture of sand and water (approximately in a 1/5 proportion) that, thanks to the ridge, settles most of the sediment before reaching the shore. Figure 7. Sand pumping system in a photo (A) and schematised diagram (B). The pipe is brought
Figure 7. Sand pumping system in a photo (A) and schematised diagram (B). The pipe is brought to the beach and placed within an artificial ridge. This pipe releases a mixture of sand and water (approximately in a 1/5 proportion) that, thanks to the ridge, settles most of the sediment before reaching the shore. Figure 7. Sand pumping system in a photo (A) and schematised diagram (B). The pipe is brought
In summary, nourishment (anthropic process) ended in May, at the moment wher swell waves (a natural process) started transporting fines from submerged zones to the dry beach, as shown in Figure 8. Figure 8. Sketch showing the upwards movement of the fine fraction of the sand by swell waves during the summer season (top) and downwards due to sea waves during the winter season (bottom).
In summary, nourishment (anthropic process) ended in May, at the moment wher swell waves (a natural process) started transporting fines from submerged zones to the dry beach, as shown in Figure 8. Figure 8. Sketch showing the upwards movement of the fine fraction of the sand by swell waves during the summer season (top) and downwards due to sea waves during the winter season (bottom).
Table 4. Sorting values for every beach and surveying campaign. Table 5. Classification of sorting values, adapted from Roman-Sierra et al. [37].
Table 4. Sorting values for every beach and surveying campaign. Table 5. Classification of sorting values, adapted from Roman-Sierra et al. [37].
Native sorting values ranged from 0.50 to 1.03 for the four beaches, therefore classify- ing these as having moderately well-sorted sands with some scarce locations of moderately sorted material (Table 5). Some of the beaches, such as SMM and VB, seemed to have almost negligible variations in their grain sizes of less than 0.2 9.
Native sorting values ranged from 0.50 to 1.03 for the four beaches, therefore classify- ing these as having moderately well-sorted sands with some scarce locations of moderately sorted material (Table 5). Some of the beaches, such as SMM and VB, seemed to have almost negligible variations in their grain sizes of less than 0.2 9.
Figure 9. Results of sorting (@ units) obtained for the established elevations (submerged, LLWL, intertidal and HHWL) in the four monitored beaches.
Figure 9. Results of sorting (@ units) obtained for the established elevations (submerged, LLWL, intertidal and HHWL) in the four monitored beaches.
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