Surf zone-related drownings and injuries based on lifeguard records in Goa beaches (2008–2020)

The study is based on lifeguard data from 44 Goa beaches over a period of 2008–2020; a total of 4837 surf zone injury (SZI) cases were analyzed. Calangute reported the highest SZIs with 24.63% followed by Baga and Candolim in the North Goa. In South Goa, Colva recorded the highest percentage of beach victims with 18.25%. Since Goa beaches are world famous, many tourists from foreign countries have become victims with a total percentage of 22.2%, thereby showing its importance to the global community. Out of all Indian states, Karnataka recorded nearly 21.93% cases as compared to Goa with 13.53%. Since there is a stringent lifeguard system available at Goa beaches, the drowning percentage is just 2.86%. Rips are found to be the primary cause responsible for most cases accounting for 59.32% with nearly 3030 victims. The secondary cause is due to shore breaking. The most common injury type is a fracture of the legs which accounts for 8.02%. Apart from rip current related cases, there are other cases reported due to tourism activities. Out of all recreational activities, wading resulted in more number of SZIs with 19.61% followed by surfing and body boarding. The SZI-related cases have also been examined based on age and gender. The predominant age group involved in the injuries was between 19 and 25 years (36.33%) with the majority of victims being males (78.59%). Few rip currents outbreak events with large number of victims rescued at Baga and Calangute beaches have been studied using multi-temporal high-resolution satellite imageries and able to identify dangerous hot spots. These details give an idea of which regions along the beaches management have to focus on and restrict the zones from any kind of recreational activities. This analysis is the first of its kind in India, where a detailed study is carried on based on lifeguard reports, suggesting the importance of rescue or drowning data.


Introduction
In recent years, many coastal regions are developed for the urbanization, social activities commercial purposes, cultural activities, tourism, etc. Nearly half of the world's population lives within 200 km of the coastal regions, and these numbers are probable to increase double in 2025 (Ferrari et al. 2019). Coastal areas represent an important source of the economy worldwide (Jiménez et al. 2007). Sandy beaches are beautiful, popular for recreation, and widely connected to tourism cultural initiatives, and therefore, millions of people visit every year (Arun Kumar and Prasad 2014;Castelle et al. 2018). However, beachgoers are unaware or unskilled of oceanic processes that take place in the nearshore and therefore resulting in surf beach dangers (Puleo et al. 2016). In general, the public represents a diverse demographic and visits beaches for a variety of recreational activities including sunbathing, wading, bodyboarding, swimming and surfing (Niels West 2005;Castelle et al. 2018). However, beaches although attractive can sometimes also be the dangerous environments. The beaches are characterized by powerful wave breaking and currents in the surf zone, which can become dangerous when beachgoers enter in the surf zone water (Short and Brander 2014;Castelle et al. 2016Castelle et al. , 2018Short and Weir 2018) leading to many surf zone injuries and even drownings.
Surf zone injuries (SZIs) are mainly affected by two reasons (i) rip currents and (ii) shore break waves resulting in spine, neck and shoulder dislocations (de Korte et al. 2021). It is well established that the primary cause of these fatal and nonfatal drowning incidents is due to rip currents on sandy beaches. Rip currents are strong and narrow flow of water, frequently originate close to the shoreline and generally flow toward offshore (MacMahan et al. 2006;Dalrymple et al. 2011;Castelle et al. 2016Castelle et al. , 2020. On the sandy beaches, different types of rip currents can occur (Castelle et al. 2016) but one of the most important and commonly understood types is Channel rips. They occupy morphologic depressions between sandbars and produced by variation in the wave breaking (Castelle et al. 2016;Pitman et al. 2021). Rips currents generally flow toward the sea with a distinctive mean velocity of 0.5-0.8 ms −1 and sometimes occasionally with magnitudes reaching 2 ms −1 (MacMahan et al. 2006;Pitman et al. 2021). Rip currents hazards are widely studied as surf zone injuries as compared to the shore break wave hazard. Shore break waves can cause a large number of injuries including spine, neck and shoulder dislocations (Robles 2006;Puleo et al. 2016). On some beaches, shore break waves may also be a primary cause of surf zone injuries (SZIs). For example, shore break waves result up to 80% of the total SZI at Ocean City Maryland (Muller 2018;de Korte et al. 2021). However, the probability of rip current drownings or beach hazards also depends on multiple social factors such as the presence/absence of lifeguards, choosing the swimming location, behavior of the beachgoer and their knowledge of rip currents. (Gilchrist and Branche 2018;Ménard et al. 2018). Figure 1a shows the behavior of beachgoers neglecting the "red flag" warning and gathered at the same location. The range of recreational activities available at Goa beaches is shown in Fig. 1b, which are primary factors for large number of SZIs (Chang et al. 2006;Robles 2006;Barucq 2009). There are many programs and interventions on rip currents around the globe to reduce the social aspects of rip current drownings. Lifeguards are established as the most effective method for saving the people from the drowning incidents on popular beaches. Recently many numbers of dedicated international campaigns have focused particularly on rip currents interventions. For example, the "US break the Grip of the Rip" campaign (https:// www. weath er. gov/ safety/ ripcu rrent), founded in 2005, mainly focuses on how to identify the rips and how to escape the rips, and why they are dangerous. Year day gathering very close to the red flag, which is supposed to be very dangerous due to rip currents, life guard on-duty on a bench close to the beach can be observed in this picture. b Photograph showing the range of recreational activities at Calangute Beach, another cause for surf zone injuries In Australia, most campaigns from 2009 onwards have been focused on how to avoid and identify rip currents and recently adopted the "Think Line" (https:// www. beach safe. org. au/ surf-safety/ rip currents), there is a "Respect the Water" campaign in the UK (https:// www. respe ctthe water. com), which is more extensive on raising awareness of the dangers represented with coastal or marine recreation. New Zealand has recently launched the three R's ("Relax, Raise, Ride") rip current campaign (http:// www. finda beach. co. nz/ besafe/ hazar ds/ rips) (Pitman et al. 2021).
In the case of India, the country is blessed with 7600 km of beautiful coastline with the majority of sandy beaches. Each state has a few unique beaches, which are popular for beach recreation. Both east and west coasts have equal number of beautiful beaches, but the former has only a few beaches, which are tourist friendly whereas the latter has a lot more tourist footfall. Apart from that, the pleasant climate, beautiful landscape and the wideshallow beaches make west coast beaches more popular. On the other hand, the east coast is more prone to cyclones and other natural hazards. The absence of mountain ranges closes to the beaches encouraged habitation and industrial development along the east coast and therefore led to less recreationally attractive. Almost in all states along the west coast, the beaches are very shallow and safe, while it tappers narrowly along east coast. Goa is such a state, where tourism is the major source of the revenue and the beaches are the backbones. It is one of the richest states in India, with two and half-times highest GDP larger than over the country, tourism is the primary financial aspect to grow the GDP. Situated in the western part of India with a 160 km long coastline, Goa has two-thirds of the most attractive and recreational sandy beaches in India. The expansive structure of these beaches attracts thousands of foreign and local tourists, for water sports activities such as surfing swimming, wading, etc. Occasionally, surf sinking is reported in some areas of the beach (Chandramohan et al. 1997). Drishti Lifesaving Ltd. (undertaken by the Department of Tourism, Government of Goa) is a professional organization that provides lifeguard services on Goa beaches and interior waterfalls. Over 700 trained lifeguards have been deployed to provide dedicated services across every beach in Goa. Additionally, the Beach Safety Patrol focus on women's safety assists tourists and deters tourists from venturing into the sea. The service has led to a 99% reduction in deaths due to drowning and significantly improved the tourist experience in Goa. Over 3,000 lives have been saved due to intervention rescue operations. (https:// www. drish timar ine. com/).

Regional settings
Goa is a small state located along the western part of India, with two districts, North Goa and South Goa, covering an area of around 3702 km 2 . It lies between the latitudes 14°53′54″ N and 15°40′00″ N and longitudes 73°40′33″ E and 74°20′13″ E. It has about 160 km of long coastline, with estuaries, sea hills, promontories, pocket beaches, dunes, hard rock wave-cut platforms, world-famous beaches, etc. The oceanic climate of Goa dominates over three seasons (1) southwest monsoon (June to September); (2) northeast monsoon (October to January); and (3) the fair-weather period (February to May). It experiences a tropical humid climate and receives rainfall during southwest monsoon winds from June to September. The annual rainfall ranges from 250 to 300 cm in this region, while temperature varies between 20 and 37° C. The sea conditions are generally rough 1 3 during the southwest monsoon and calm during the rest of the year (Chandramohan et al. 1997). There are around 44 beaches in Goa out of which 18 beaches are there in North Goa and 26 beaches in South Goa. Mainly 20 beaches are famous for the tourism industry. Figure 2 shows the beach locations used for data collection, where lifeguards are deployed round the clock to prevent and protect the beachgoers from the drowning risk. Surf zone injuries (SZI) data were collected and maintained by Drishti Lifesaving Pvt. Ltd. (hereafter DLPL), which provides professional lifeguard services on behalf of the Department of Tourism, Goa. Unlike other countries, where lifeguards are usually deployed only during the peak tourist season, Goa beaches are patrolled throughout the year. The beaches are patrolled both north and south of the bathing area, although those regions are restricted for swimming. The bathing zone is generally located on a shore-connected shoal, where waves break and typically away from the rip channels. All the beaches are patrolled using fourwheel drive jeeps from 6 AM to sunset (depending upon the season) although lifeguards are present throughout the day even after patrolled hours. All beaches are closed for any kind of bathing or swimming activity during rough sea state conditions associated with storms or monsoon.

Data and methodology
Lifeguards patrol the entire beach and define some places with strict restrictions like bathing and swimming prohibition, etc. (de Korte et al. 2021). Some beaches along this coastline have totally unrestricted areas. Lifeguards are responsible for the implementation of the surf rescue and beach regulations. They are responsible for medical emergencies and for providing medical first aid before ambulance or medical services arrives at the beach. During the patrolling time, they hoist flags within 10 m with different combinations of colors indicating level of the risk (1) the green flag-safe and swim area with lifeguard on-duty, (2) yellow and orange flags-dangerous for bathing, but monitored and (3) red flag-swimming strictly prohibited, where the danger could be due to rough sea conditions, submerged rocks, submerged hazardous objects, area prone to the formation of rip currents, sudden drop in seafloor depth, presence of harmful marine creatures, etc. They are sometimes hoisted due to pollution in the waters or lightning, which could be harmful to the beach users. Whenever there is a medical incident on the beach, the lifeguards respond to the scene by providing the care and assisting with paramedics.
The chief lifeguard is responsible for verifying the incident, including victim information and surf conditions at the time of the incident, and reporting to the higher authority in an appropriate format. When an incident occurs, a report will be generated by the lifeguard on-duty in a prescribed format (Fig. 3) and are sent to the headquarters for compilation. The lifeguard report includes injury/accident date, time of injury, gender, age, nationality, cause of injury, health conditions (e.g., conscious and unconscious), location of the incident (e.g., swim zone, non-swim zone, beach operation status, etc.), cause (e.g., rip currents, shore-break waves, etc.) and injury analysis (e.g., spinal injury, cervical strain, dislocated shoulder), body region (e.g., lower extremity, upper extremity, face), displacement (e.g., sent home, call to ambulance, admit, sent to hospital), incident leading to injury (e.g., thrown on surf, wave, tide, hit by body board), activity type (e.g., wading, surfing, boarding, watersports, etc.). In this work, the SZIs reported data were checked and corrected for any errors and anomalies (da FKlein 2003). For example, there were at times data appeared in twice at the same time, and in other cases gaps were found. All the data related to SZIs were carefully reviewed and corrected for any such anomalies (Brewster et al. 2019).

3
In contrast to the SZI reports from other countries, rip currents are not pre-defined as an incident cause. Instead, those incidents are deduced from the detailed comments provided in the "Details of the Incident and Casualty type" where the beach user was caught in the rip current mentioned explicitly. Arun Kumar and Prasad (2014) used a  beach. This would enable the beach managers to take preventive actions against such dangers in the future and could able to identify the rip current hot spots.
The variables from the lifeguard logs are scrutinized as follows: date, location of the beach (beach name), incident starting time, incident ending time, flag colors, swimming zone or non-swimming zone, age, gender, nationality of the victim(s) with full postal address, activity (watersports, wading, swimming, surfing, bodyboarding, etc.), cause of injury (rip current, tide, shore break, suddenly wave attack to falling the water and others), type of injury (sinking, injury/ contusion, spine/cervix, break the bones/ luxation and, etc.). Sometimes, when the lifeguards are absent, the beach in operation that time will be closed to beachgoers. The drowning phase is presented according to a 4-step classification, ranging from mild to very severe: (1) fatigue, but no sign of water aspiration, (2) moderate respiratory weakness or anxiety, (3) altered consciousness, severe respiratory failure, or severe pulmonary edema, tachycardia or hypotension and (4) coma, respiratory or cardiac arrest (Castelle et al. 2020). The total data used in this work were gathered over a total of 40 Goa beaches between October 2008 and March 2020. North Goa consists of 16 patrolled beaches whereas South Goa has 24 beaches. A total of 4837 injury data were reported during the study period (please refer to Tables 1 and 2). Partially filled forms and the reports without proper formatting were discarded from the study in order to avoid confusion.

SZI analysis
Goa coast hosts some of the finest beaches in India attracting many tourists worldwide. These beaches are mostly visited by foreign tourists apart from the Indian tourists throughout the year. Highest footfall is observed in North Goa beaches, viz. Baga, Calangute, Candolim and Arambol, with most people visit the beaches during November-March. In general, the coast is exposed to high energy ocean swells approaching from 230° to 280° with the variation of significant wave height between 0.8 and 5 m (average-1.8 m) (Kumar e t al. 2000;Vethamony et al. 2011). During southwest monsoon, the wave heights exceed 2.5 m at Candolim, whereas at other beaches it ranges between 1.0 and 1.5 m (Chandramohan et al. 1997;Yadhunath et al. 2022) The foreshore of almost all the beaches is wide and relatively steep at its extreme ends. They are backed by well-developed dunes at some places and by permanent buildings at tourist places. The width of the beach varies between 50 and 200 m but trimmed with 1-10 m well-developed sand dunes. Calangute beach has dunes that vary in length from 0.5 to 10 m. The foreshore width of Calangute ranges around 40-60 m, whereas Baga beach is relatively narrow with a backshore of few meters wide and moderately steep foreshore (Veerayya and Varadachari 1975;C S MURTY 1982;Tripati et al. 2002). Past studies reveal the existence of prominent rip current occurrences along this stretch (Antony 1976;Kumar et al. 1989;Chandramohan and Nayak 1992;Chandramohan et al. 1997;Prakash et al. 2021;Yadhunath et al. 2022). The beaches north of Zuari River mouth are straight, while other beaches south of this river are backed by rocky hills. The entire stretch of Baga to Sinquerim is popular for water sport activities and with many beach resorts.
A detailed statistical analysis was performed on the data to capture the main features of surf zone-related incidents and events, in particular, to understand the relationship between SZI and individuals. The spatial distribution of surf zone injuries that happened on these beaches during the study period is plotted according to the victim's address (state/country) in Fig. 4a, b. Out of all the victims, Indians were 77.3% (n = 3807) and foreigners were 22.2% (n = 1095). It has been observed that victims from Karnataka account for the highest number of SZIs with 21.93% (n = 835), which could be due to its close proximity to Goa beaches, followed by Maharashtra 19.41% (n = 739), Goa 13.53% (n = 515) and Delhi 5.17% (n = 212). Most victims were non-locals which is consistent with the trends found elsewhere (Castelle et al. 2018). Higher number of SZI cases were reported (n = 775) with around 24.63% from Calangute, 23.39% (n = 736) from Baga and 12.01% (n = 378) from Candolim, whereas in South Goa, highest percentage of beach victims are from Colva with 18.25% (n = 327), followed by Palolem 14.21% (n = 251) and Benaulim 10.34% (n = 179). Most of the victims from foreign countries belong to Russia, England, Australia and the USA. Although the study seems to be regional pertaining to a few beaches in Goa, due to its popularity across the world, many foreign people who visit the beaches fall victims to the surf zone hazards, particularly the rip currents. Fig. 5 provides an overview of SZI types including primary cause, injury type and activity of the beachgoer at the time of the incident. Deaths due to drowning only cover 2.86% Table 1 Year-wise demographic injury data from all the beaches of North Goa between 2008 and 2020 (n = 3147) Top 3 beaches with the highest percentage of injuries are marked ranks against its name Beach name  Table 2 Year-wise Demographic injury data with all the beaches of South Goa between 2008 and 2020, n of the injuries (Fig. 5a). It has been found that the primary cause of the SZIs is due to rip currents totalling around 59.32% (n = 1948) incidents and 61.50% (n = 3030) victims. Males contribute to nearly 48.63% of (n = 2396), a large portion as compared to females (12.87%; n = 634) ( Table 2). Followed by rip currents, another primary cause was due  to shore break accidents in crowded bathing zones, which contribute to around 12.22% (n = 602) male, 3.43% (n = 169) female. Wave attack is relatively less, where males contribute to 4.99% (n = 246) and 1.93% n = 95) by females. There were a greater number of incidents when the people venturing into the surf zone become panicked and leading to health issues like heart attack, etc. They contributed to nearly 8.30% (n = 409) in males and 1.99% (n = 98) in females. Around 2.86% (n = 141) dead bodies were recovered during the study period with around 2.39% (n = 118) were males and 0.47% (n = 23) were females.
Apart from the beachgoers who are comforted and released after rescues, the majority of around 19.97% were admitted to the hospital. The most common injury type is a fracture of the legs (8.02%) followed by injuries in bones, spinal or bleeding (4.38%) and knee injuries (4.2%). Several other injuries like a neck injury, small wounds and pains were also reported, which did not require any further medical assistance. Apart from rip currents and accidents due to water sports activities, shore-break waves (wave attack) are the important cause of SZIs (6.92%, Fig. 5a), which would have increased the risk with beachgoers doing wading, bodyboarding and surfing. Getting panic (10.29%) is one of the major causes of the rescue either when a people get in a rip current or involved in any other beach activity. This shows that most of the people are unaware about the hazards posed in the beaches. The hazard would become even danger when the beachgoer is drunken. Around 18.65% of beachgoers were in a drunken state when a rescue happened. Figure 5c shows a large proportion of surf zone injuries are related to wading (19.61%), surfing (14.21%) and bodyboarding (9.78%) activities as evidenced by the large proportion of knee injuries, neck injuries, bleeding, etc. Wading is primarily responsible for a greater number of cases with around 26.95% (n = 885) and around 19.61% (n = 966) victims were befallen. Out of these, 12.60% (n = 621) were men and 7.0% (n = 345) were women. Due to a large number of people entering the surf in a drunken condition, the SZIs are more recorded when the victims were in a drunken state. Around 23.11% (n = 759) incidents with 18.65% (n = 919) victims were recorded. Very few females were observed in this condition with 1.22% (n = 60) but a large proportion is from males 17.43% (n = 859). Although surfing is uncommon in Goa beaches, surfing incidents contribute to around 18.36% (n = 603) with 14.21% (n = 700) victims. Bodyboarding also contributes around 10.87% (n = 357) incidents with 9.78% (n = 482) victims. Accidents due to water sports activities are very minimal, where around 6.52% (n = 214) incidents with 6.39% (n = 315) victims were observed. It represents that the water sports activities take much care during the operations. However, despite such care, some incidents might happen due to unknown or unforeseen reasons (Brighton et al. 2013). Other activities include rock/ cliff-related, rather than fishing and scuba diving, which are although relatively high but uncommon at every place. This analysis is however limited to non-conclusive analysis due to certain data gaps. Table 3 provides more insight into the drowning population and shows that there is a large majority (74.1%; n = 33) of males involved in severe drowning incidents (stages 3 and 4), while milder drowning incidents (stages 1 and 2) are approximately equally distributed between males and females. Overall, 79% (n = 222) of the drowning incidents are caused by rip currents, a proportion that ranges from 50 to 82% depending on the drowning stage (Table 3). Figure 6 shows the primary cause, injury type and activities of a beach goer at the time of the incident reported. The majority common type of SZI is comforted/ released 48.75% (total n = 2402) victims and 37.83% (n = 1864) men, 10.92% (n = 538) women, followed by illness/ hospital 19.97% (n = 984) victims 16.18% (n = 797) men, 3.80% (n = 187) women, fracture of legs 8.02% (n = 395) victims and 6.15%(n = 303) men, 1.87% (n = 92) women, bones/spinal/bleeding victims were 4.38% (n = 216), 3.63% (n = 179) men, 0.75% (n = 37) women. 4.20% (n = 207) knee injury victims were found, in 3.11% (v= 153) of men, 1.10% (n = 54) women were identified. Suspected neck injury counts were identified 4.95% (n = 244), 3.94% (n = 194) of men, 1.01% (n = 50) women. Bandage / wound 4.08% (n = 201) victims, 3.31% (n = 163) men, 0.77% (n = 38) women. Rip currents are the major cause for the surf zone rescues contributing to nearly 2380 males and nearly 620 females. Drunken males (n = 823) contributed to maximum number of cases as compared to females (n = 25). Few of beachgoers needed first aid with 8.10% (n = 399) out of which 6.45% (n = 318) were the men, 1.64% (n = 81) were the women. Coming to total drowning incidents of 6.05% (n = 298), 5.32% (n = 262) were the men, 0.73% (n = 36) were the women. Maximum beachgoers were in conscious state when they were rescued, which is around 87.31% (n = 4302) victims. Few of the data were missing when an incident happened. Data missing means, they were recorded the incident but no information of the victims were made available, such data were discarded from the analysis.
The predominant age group involved in the surf zone incidents was between 19 and 25 years (36.33%), with the majority of victims involving males (78.59%), whereas females comprise of 20.85%. Figure 7 shows the age-wise distribution of the surf zone incidents for the entire dataset. The distribution for any specific activity like surfing, wading, etc., or the injury caused by wave attack, rip currents, etc., and even major incidents like spinal/bone injuries are shown in other panels in Fig. 7. However, the distribution of age group within gender was non-normal, injured females are more than males within 0-18 and 36-60 group and less than males within 19-35 age. Out of these, females were injured on around 30% were between 19 and 25 years age, 28.98% (26-35 years), followed by 11.16% (36-45 years) and so on. This suggests that the female youth between 19 and 35 are becoming more prone to the surf zone danger. This could be either due to negligence in following appropriate surf zone behavior while venturing into the sea, or unaware of such dangers, or less skilled in handling such hazards (McCool et al. 2008).
The median and mean ages from the dataset were 27 (19) and 30 (26) years for males (females), respectively. Same age and gender distributions are observed for surfing activity (Fig. 7b) for the ages between 0 and 18 years. Wading is mostly done by females of age 13-25 years. The wave attack/shore break-related injuries are more in males for ages 19-25 and females for ages 26-35, 60 + . In contrast, the population injured due to rip currents is younger with 66% within the age group 19-25, followed by 26-45 years. The spine injured people are also observed within 19-25 years, which is almost similar to wading injuries. The drowning people are high within the age group 46-60 years followed by 19-35 years. Only male children were drowned within the age 0-12 years. The percentage of injuries in the non-swim zone is seen more in males of age 19-25 years. Still around 10% of children (0-12 years) were injured in the non-swim zone. Most of the incidents were happened in Table 3 Activity wise distribution of surf zone injuries related to gender, location (swim or non-swim zone) and causes Activity/ Cause  Male  Female  Swim zone  Non-swim zone   Surfing  583  117  45  122   Wading  621  345  61  132  Bodyboarding  380  102  59  69  Water sports  280  35  82  51  Wave attack  246  95  226  386  Health issue  409  98  127  159  Rip currents  2396  634  702  1020 1 3 Fig. 6 Gender distribution of surf zone victim count related to (a) Primary cause b Incident type and c Activity of the victims the non-swim zone with around 1370 (41.72%) cases and nearly 1939 (39.35%) victims were suffered. Out of these, 31.22% (n = 1538) were men and 8.14% (n = 401) were women (Fig. 7). Non-swim zones are often identified by the Lifeguard on duty as most dangerous for bathing for any kind of activity and are usually restricted. Non-swim zones are often consisting of dangerous and sharp or slippery rocks, sudden changes in the depth persistent for many days, or any marine animal hazard. These zones are identified every day by the lifeguards and flagged appropriately. However, some people do not follow the lifeguard's advice and get into trouble. On the other hand, swim zones are not categorized as safe zones. They are otherwise, well known and monitored by a team of lifeguards. These zones are relatively near to the beach entrance and occupied by many beachgoers in general. In the swim zone, around 1302 (26.43%) incidents happened with nearly 916 (27.89%) victims were befallen. Men (19.77%) contributed to a greater number of incidents as compared to the women (6.66%). When the beach was closed with red and yellow flags, there were a total of 646 (19.67%) incidents happened with 939 (19.06%) victims. When the beach was closed for swimming, around 43 incidents (1.31%) were found with 128 victims (2.60%) (Fig. 8). All the SZIs reported with latitude and longitude information were plotted over popular tourist beaches in the North Goa and shown in Fig. 9. It can be observed that Calangute appears to be most dangerous hot spot, with big cluster of rescues/drownings followed by Baga. The highest number of rescues happened near to the lifeguard tower, whereas it is located in between the two Baga towers (Baga-1 and Baga-2 as shown in the Fig. 7 Age and gender distribution of SZIs for (a) total incidents within the swim zone; b surfing; c wading; d spinal or bone injuries; e injuries due to wave attack; f injuries due to rip currents; g drowning deaths and h injuries in non-swim zone map). It is indicative that large cluster of cases in Calangute is linked in highest footfall of beachgoers in addition to the rip current risk. The entire beach stretch between Baga-1 and Baga-2 lifeguard towers are in risky region. On the other hand, more number of cases were reported in between Candolim-2 and Sinquerim beaches, with almost negligible cases at their respective towers. A few cases were reported south of Sinquerim tower. Therefore, it is suggested to shift the lifeguard towers at Candolim-2 and Sinquerim toward south to efficiently manage the lifeguards.

Rip current detection from satellite imageries
In general, although rip currents are transient in nature, bathymetrically controlled rips are stable over a period of time and they appear around the same region every year. From the above section, it is clear that Baga and Calangute are worse in SZIs with highest contribution by the rip currents. To understand this, multi-temporal high-resolution satellite imageries from these beaches have been processed and identified rip current (channel) features. The instantaneous rip current features from 2010 to 2019 obtained from Google Earth at Baga beach and Calangute beach are shown in Figs. 10 and 11. The rescues recorded on the date of satellite acquisition with a temporal window of ± 3 days are noted in Table 4. All the recorded rip current rescues for 7 days period with satellite image date as centre are noted, during which most of the bathymetrically controlled Channel rips remain unchanged. It can be noticed that there are 9 such high-resolution images obtained over both Baga and Calangute beaches to examine the possibility of rips and its connection with the number of rescues. Although, rip current signatures (break in the wave pattern, sediment plume, rip channels) are not clearly visible on all the imageries under consideration, a few images with significant features of any of the above signatures are highly coincident with the large number of rescues. For example on 22nd October 2015, a record number of 8 cases were logged with 16 victims from Baga and Calangute, trapped in rip currents and saved by the lifeguards. A closer look at the figures reveals a significant three rip channels with orientation toward northwestward can be seen in Baga, while a distinct discoloration of surf zone with sediment plume can be seen in Calangute. In another day of 16th October 2016, total of 12 victims in 5 cases and 18 victims in 9 cases were recorded in Baga and Calangute beaches, one of the highest rescues reported during the period of study. A large number of rip currents laden with sediments can be clearly observed in the Figs. 10 and 11e. The satellite images have been enhanced by increasing the contrast by 20-30% in all the images so that these signatures are visually discernable. Out of all these nine images, three were recorded during low tide periods i.e., 26th November 2016, 12th December 2017 and 05th November 2018. Very clear evidence of rip channels with dark waters surrounded by sediment bars can be seen in these images. Especially, the image on 12th December 2017 is a clear evidence of rip current danger at Baga and Calangute beaches. Persistent rip channels were present continuously all along the 7 km beach with sediment bars welded to the beach at some places, representing Transverse Bar and Rip beach stage-TBR (Wright and Short, 1984). Interestingly, due to measures taken by the lifeguards, the number of rescues were relatively less (3 cases; 7 victims in Baga and 1 case; 4 victims in Calangute). On 7th November 2019, there were persistent gaps in the breaker zones indicated by red arrows on the images. A total of 5 rips were present at Baga beach and 3 rips at Calangute beach. As October-December is peak tourist season in Goa with footfall of more than one lakh people from all over the country and foreign countries, a record number of 25 cases with 45 victims were rescued only at these two beaches. Other beaches like Candolim and Sinquerim, which are also located along the same beach stretch toward south are not crowded much (Fig. 9). However, few cases were also reported at these two beaches. This analysis shows that the rip current rescues recorded by the lifeguards are well matching with the actual rip currents existence.

Conclusions
A detailed study on surf zone injuries (SZIs) has been carried out using lifeguard data from nearly 44 Goa beaches in India for the period of 2008-2020 to examine different kinds of injuries and its relationship with the beachgoer's activities, gender, place, etc. Goa being the India's top most tourism capital and its popular beaches, we found there is a global significance in studying the SZIs. Out of all the beaches, Calangute reported the highest SZI cases followed by Baga and Candolim in the North Goa and Colva being highest in the South Goa. Reasonably highest number of incidents happened from the people of Karnataka followed by the locals. We found that rip currents are one of the primary causes of SZIs contributing to nearly 59.32% of total cases with nearly 3030 victims followed by injuries due to shore breaking. Based on the analysis, we determined that victims of age between 19 and 25 were suffered SZIs most and male victims are dominant in all injury types. Although beyond the scope of this paper, the physical, cultural and social reasons why youth are highly exposed to these injuries should be explored further. Drunken people have contributed to more number of rescues; which suggests the availability of liquor in the beaches to be streamlined. There is a highly spatial variation in the SZI data along the entire Goa coast, with major hot spots being concentrated at Calangute and Baga beaches. Therefore, some additional measures have to be taken by the planners to manage the crowd at these beaches such as facilities with Automated Beach Alarming system, enhanced video monitoring, availability of lifesaving jackets for the beachgoers etc., could be helpful. On the other hand, beaches with negligible SZI cases need to the explored and further developed for recreational activities like sports, additional development of resorts, so that the beachgoers can choose a better place for their safety. The absence of long-term wave, tide and weather data is another drawback of Goa coast, where systematic data is not available to examine the relations between forcings and injuries, this will be a subject of a future study as a key contribution of this present effort. The major outcome of this work is that, it is revealed that rip currents clearly represent a major hazard to beachgoers in Goa and are by far the leading deadly surf zone hazard. This analysis helps the beach managers to focus on specific beaches and administer restrictions in the beaches with minimum effort. Accurate incident reporting is another major challenge for a lifeguard. Although they are efficient in reporting the incidents, many reports were partially reported due to which have to be discarded from the analysis. This can be fulfilled by utilizing real-time recording of events through mobiles or smartphones by way of customized applications, which will be attempted in the future. Irrespective of these limitations, our study provides the first overview of the SZIs in Goa and reveals its global significance. While the most severe injuries and fatal drownings are related to rip currents, a large number of SZIs occurred as a result of shore-breaking and sport activities, primarily within and outside the patrolled zones. The predominance of young males was found in most SZI cases in non-swim zones, while surprisingly high number of fatal drowning incidents were reported in females and the people aged above 45. Therefore, it is necessary to run beach campaigns to create awareness among all the beachgoers irrespective of their age and gender to emphasize the importance of using surf zone only between the flags and in the presence of lifeguards. Proper warning boards should be placed at beaches with high number of reported SZIs.