Flash Flood Warning Siren System: Maintenance and Operations Manual

Document No.: FFWS-OPS-2026-001 System: Flash Flood Warning Siren Network, [] Creek Corridor Prepared for: [] County Emergency Management Office Prepared by: [Installation Contractor] Date prepared: April 2026 Approved by: _______________ Approval date: _______________ Next scheduled review: April 2027

This manual covers maintenance, testing, and operational procedures for the flash flood warning siren system installed under the TWDB Flood Infrastructure Fund. It is to be held by the designated responsible party (Section 2) and updated annually, or sooner following any system modification, component replacement, or change in responsible personnel.

1. System Description

Equipment: Electronic omnidirectional warning siren Rated acoustic output: 121 dB at 100 feet (manufacturer specification, ideal conditions) Power supply: Solar panel array with 24V sealed lead-acid battery bank Communications: Dual-path — VHF radio (primary), cellular modem (secondary) Activation method: Remote activation from County EOC; automated NWS alert feed (if configured) Number of stations: ___ Installation complete: [Month] 2026 Warranty expiration: ___

Each station comprises a multi-cell speaker array with an independent amplifier per cell, an electronic controller with tone generator, a battery cabinet and charger, a solar panel with charge regulator, a VHF antenna, a cellular modem, lightning protection, and a galvanized steel mounting pole. The system produces steady, wail, and attack tones. Stations equipped with public-address input can broadcast voice messages.

2. Responsible Parties

Under the TWDB grant program, the county, or an entity contracting with the county, is responsible for maintenance and equipment upkeep once installation is accepted. If the county designates a contracting entity, reference the written agreement here and attach it as Appendix D.

[Field note, 7/2026: No maintenance contract has been executed. County judge's office indicates this is pending. All inspection tasks in Section 3 are currently unassigned.]

2.1 Personnel Succession

When the emergency management coordinator position is vacated, complete the following within ___ business days:

Succession procedures for the emergency management coordinator position are established in _______________. See Appendix ___ (not attached).

3. Inspection and Maintenance Schedule

Inspection tasks follow manufacturer maintenance documentation at the intervals below. Perform an additional inspection after any severe weather event affecting the coverage area.

3.1 Quarterly Physical Inspection Checklist

For each station, record station number, siren address, inspection date, inspector name, and condition (OK / NOT OK with comments) for each item:

• Mounting hardware and pole condition (plumb, corrosion, shifting)
• Speaker assembly (physical damage, loose hardware)
• Cabinet (forced entry, debris, rodents, insects, drain holes clear)
• Solar supply (connections, fuses, charge indicator)
• Grounding and lightning protection
• Conduit connections (watertight)
• Battery terminals (corrosion, coating)
• Wiring harnesses (chafing, loose terminations)
• Antenna and cable (secure, no damage)
• Cellular modem (status indicator)

Note: Newly set poles and hardware settle over the first several years of service and will require retightening. Budget accordingly.

4. Test Procedures

4.1 Remote Diagnostic Test (Twice Monthly — Silent)

1. From the primary activation point, initiate a diagnostic command to Station [#].
2. Confirm the controller acknowledges the command via status return.
3. Record battery voltage, amplifier channel status, and communications signal strength from the status report.
4. Repeat via the secondary communications path.
5. Log results in the station performance log. A failed status return, or any channel fault, is a failure. Notify the designated maintenance entity.

[Field note: If the system is configured to send automatic fault notifications to emergency management staff, confirm the notification path is active and the receiving contact is current. Where the receiving contact has changed roles or left the position, the notification path is inactive. The system will continue reporting faults into it.]

4.2 Full-Volume Activation Test (Annually, or Monthly Where Locally Required)

1. Issue public notification of the scheduled test per county communications plan.
2. From the primary activation point, activate all stations in wail tone for three minutes.
3. An observer at each station confirms audible output. Record: station number, tone heard (yes/no), perceived output (normal/reduced/none), weather conditions, ambient noise.
4. Repeat activation via the secondary communications path.
5. If the system is voice-capable, transmit a test voice message. Observer confirms intelligibility at the station location.
6. Log all results. Any station not confirmed audible by the observer is a failure.

Pass criteria: Command transmitted. Station acknowledged. All amplifier and driver channels within tolerance. Audible output confirmed by an observer at the station location.

This procedure confirms signal generation, transmission, and audible output at the pole. It does not verify audibility at the coverage boundary, audibility indoors, or public comprehension of the signal's meaning.

4.3 Post-Maintenance Test

Following any corrective maintenance or component replacement, perform a diagnostic test (4.1) and a single-station full-volume activation to confirm the repair before returning the station to service.

5. Troubleshooting

6. Replacement Parts and Inventory

[Field note: Manufacturer recommends battery replacement every 2–3 years. Climate, activation frequency, depth of discharge, and attached equipment all shorten that. At [#] stations, estimated battery replacement cost per cycle is $[_______]. This cost recurs for the operational life of the system. No line item for recurring battery replacement appears in the county's current budget. See Section 8.]

7. Sound Coverage

The coverage map (Appendix B) shows the area where the siren signal is modeled to reach 70 dB, roughly 10 dB above an assumed ambient noise level of 60 dB, under the following conditions:

• Clear sky, calm wind
• Unobstructed line of sight from station to receiver
• Receiver outdoors
• Ground surface: grass and low vegetation
• Attenuation: approximately 6 dB per doubling of distance

Factors that reduce effective coverage during a flash flood event:

• Rainfall noise. Heavy rain raises ambient noise levels across the 500 Hz to 1 kHz band the siren occupies. Signal-to-noise at the coverage boundary falls as rainfall rate rises, and the rainfall rates that produce flash flooding on this corridor are the high ones.
• Wind. Wind along the creek corridor refracts sound and can open acoustic shadow zones upwind of the station, nearer to the pole than the coverage map predicts.
• Terrain. The corridor itself, the bluffs, and structures between station and listener can add up to 20 dB of attenuation not reflected in the coverage model.
• Indoor listeners. This is an outdoor warning system. It should not be expected to provide reliable notification to persons indoors, particularly with windows closed.

The coverage map depicts modeled performance under clear, calm conditions. It does not depict effective coverage during the weather conditions that trigger siren activation.

8. Funding and Sustainment

Grant final invoice deadline: August 1, 2027. No reimbursement requests accepted after this date.

Post-grant responsible entity: The county, a municipality through written agreement, or another entity contracting with the county.

Post-grant maintenance budget: _______________

Post-grant maintenance budget approval date: _______________

[Field note: Grant funds cover equipment and installation, both of which are complete. The rows above with no funding source entered are the recurring ones. Responsibility for entering them belongs to the entity named in Section 2 under Designated Maintenance Entity.]

9. Appendices

• Appendix A: Station location map with coordinates
• Appendix B: Sound coverage map (modeled, clear-sky conditions — see Section 7)
• Appendix C: Station performance logs (blank)
• Appendix D: Maintenance entity agreement — [not attached]
• Appendix E: County activation protocol — [not attached]
• Appendix F: Public notification and education plan — [see grant deliverables]

10. Revision History