In September 2024, 500 experienced swimmers lined up for the Chicago River Swim. Originally planned for the city’s namesake river, the race was shifted to Lake Michigan after officials raised safety concerns. Despite years of planning and input from the U.S. Coast Guard, fire, and police departments, organizers were denied a permit for the river course. Their ability to pivot highlights two critical lessons: work early with city agencies, and be ready with a backup plan.

This high-profile case underscores a reality every race director faces: even the best-prepared plan can be overruled, and flexibility is essential.

Case Study: Lake Berryessa Open Water Swim (Napa, CA)

The Lake Berryessa Swim, hosted annually by the Davis Aquatic Masters, is one of the longest-running open-water events in the U.S. Each June it welcomes 500+ athletes and executes one of the most detailed safety operations in the sport.

Safety Coverage

• 3 motorized rescue boats
• Dozens of kayakers, canoes, and SUPs
• A minimum ratio of 1 paddle craft per 25 swimmers per mile
• A dedicated “sweeper” kayak behind the final swimmer in every wave

Swimmers are tracked with numbered caps and RFID timing chips. A start gate ensures every entrant is accounted for from the first stroke to the finish.

Medical Support

• Five EMTs/paramedics on-site
• Ambulance on standby
• 35–40 minute mapped transport route to the nearest hospital

Communication

• Safety and Race Directors on a dedicated radio channel
• Cell phone backup
• On-site lightning detectors to trigger race suspension or cancellation

Post-Race Accountability

Timing chips and finish records confirm every swimmer exits the water. Any missing athlete triggers a step-by-step protocol: video/timing review, contacting emergency numbers, and immediate waterside search with the Napa County Sheriff’s marine unit.

This combination of rigorous tracking, medical presence, and clear emergency response has allowed Berryessa to safely manage large fields year after year.

Swimmer Tracking and Accountability

At scale, accountability is everything. Organizers rely on:

• Numbered, color-coded swim caps by wave
• Timing chips on ankles with start/finish mats
• Kayakers and lifeguards stationed every 100–150 yards
• A sweeper kayak to ensure no swimmer is left behind

Post-race audits compare finish data to start lists. Any discrepancy activates the missing swimmer plan, with volunteers and officials coordinating a search.

Emergency Response Coordination

Every event needs a Safety Director and Medical Director to liaise with local services-police, fire, EMS, and, for open water, maritime authorities.

A typical chain of response:

1. Lifeguard radios for help.
2. On-site EMTs respond.
3. If needed, 911 is called and transport arranged.

Volunteers must be empowered to call 911 directly. For mass emergencies (lightning strikes, multiple distressed swimmers), race officials use pre-arranged signals like horn blasts to halt the event and deploy all assets.

Medical Planning and First Aid

Best practice is at least one paramedic-level provider per 100–200 athletes. Coverage should include:

• Medical tent with oxygen, AEDs, blankets, hydration supplies
• On-site ambulance for transport
• Post-race monitoring for hypothermia or heat illness

Case law from U.S. triathlon fatalities has shown that inadequate on-site medical support exposes organizers to liability. Budgeting for strong medical staffing is non-negotiable.

Weather and Course Contingencies

Weather can endanger even the best-prepared races.

• Lightning: Suspend immediately. Do not restart until 30 minutes after the last strike.
• High winds/waves: Establish cutoff criteria (e.g. >1 foot waves) and prepare alternative courses.
• Cold water (<60°F): Require wetsuits, add medical support, and shorten or cancel the swim if necessary.
• Pollution or unsafe currents: Directors should reserve authority to postpone or cancel.

The key is publishing criteria in advance and communicating them clearly on race day.

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Volunteer and Lifeguard Coordination

Large swims depend on volunteers-sometimes hundreds. Strong planning means:

• Target ratios of 1 lifeguard per 15 swimmers
• All volunteers arrive early (often before 6 AM) for check-in, assignments, and course checks
• Briefings covering course layout, spotting duties, and emergency signals
• Credentials checked-lifeguards, CPR, and first aid certifications verified
• Post-race sweeps to recover buoys, radios, and equipment
  

Communication Systems

When emergencies happen, clarity saves lives. Standard protocols include:

• Two-way radios for directors, medical staff, and kayak leads
• Separate safety channel (not clogged by general operations)
• PA system or patrol boat horn signals for mass instructions
• Backup cell phones in case radios fail
  

Volunteers must know the horn or radio signals for stop, suspend, or abandon swim. At Berryessa, three blasts from a patrol boat horn meant “abandon swim”-a signal tested during volunteer briefings.

Key Lessons for Organizers

1. Engage authorities early. Permits and approvals can override the best-laid plans.
2. Cap entry or wave sizes. Keep swimmer-to-guard ratios manageable.
3. Staff generously. Aim for better than 15:1 swimmer-to-lifeguard ratios, plus multiple motorboats.
4. Communicate constantly. Radios, briefings, and backup systems are essential.
5. Prepare for weather. Have lightning and surf cutoffs, plus Plan B courses or duathlon options.
6. Scout the venue. Identify currents, obstacles, and traffic risks well before race day.
7. Train volunteers. Use experienced lifeguards; equip shore volunteers with radios/binoculars.
8. Account for every swimmer. Timing chips or checklists plus a formal missing-athlete protocol.

Organizers of large open-water swims must treat safety planning as the race’s foundation. The Chicago and Berryessa examples illustrate how layered risk management-tracking, medical support, communications, and weather protocols-create a true safety net.

For participants, these measures often go unnoticed. For organizers, they are the difference between a smooth event and a crisis. Investing in safety not only protects athletes but also builds credibility, trust, and longevity for the event itself.