Off-Grid Solar Flood Early Warning & Hydrological Monitoring Station

Overview

Redcoast's RC-FWS-200 Off-Grid Solar Flood Early Warning & Hydrological Monitoring Station is a self-powered, IoT-connected field cabinet built to continuously measure water level, rainfall and related hydro-meteorological variables at rivers, streams, urban drainage outfalls, dams, culverts, bridges and flash-flood-prone wadis. It is engineered for unattended operation in remote, grid-less, climatically harsh environments and is designed for hydrology bureaus, municipal flood-control agencies, water utilities, road authorities and system integrators delivering early-warning networks. By combining non-contact radar level sensing, WMO-compatible tipping-bucket rainfall measurement, a Redcoast-designed MPPT and signal-conditioning PCB stack, and an edge-intelligent IoT gateway, the station delivers reliable real-time data, threshold-based alarms and optional local siren/strobe warning — letting authorities act minutes, not hours, before a flood event escalates.

Key Features

• Non-contact 80 GHz FMCW radar water level sensor with millimetre-class resolution, immune to spray, foam, floating debris, humidity and temperature drift
• WMO-compatible tipping-bucket rain gauge interface (0.2 mm resolution) with hardware debounce, surge protection and self-clean event reporting
• Redcoast-designed signal-conditioning PCB exposing SDI-12, RS-485 Modbus, isolated 4–20 mA and digital pulse channels in parallel
• Custom MPPT solar charge controller with low-temperature charging cut-off, over/under-voltage protection and full battery health telemetry
• LiFePO4 battery pack engineered for 7–14 days of full autonomy with zero solar input
• Edge-intelligent IoT gateway with configurable rate-of-rise alarms, multi-stage water-level thresholds and store-and-forward buffering
• Multi-bearer communications: 4G LTE, NB-IoT, LoRaWAN and optional Iridium SBD satellite for sites without cellular coverage
• Optional integrated siren + RGB strobe warning beacon for in-situ public alerting at flash-flood crossings
• Optional HD camera with edge snapshot/video capture on alarm event for visual verification
• Lockable IP66 cabinet on a powder-coated mounting pole or bridge bracket; modular, field-replaceable sensors, radio, battery and PCB stack

Technical Architecture

The RC-FWS-200 is built around a Redcoast-engineered three-board PCB stack housed in the station's IP66 cabinet. The bottom board is the MPPT power-management board, which extracts maximum power from the solar array, manages charging of the LiFePO4 pack with full temperature compensation, distributes regulated 12 V and 3.3 V rails, and exposes battery state-of-charge, cell voltages, current and temperature over an internal I²C bus.

Above the power board sits the sensor signal-conditioning board, a Redcoast custom PCB that handles the mixed-signal interfaces hydrological deployments demand. It provides an SDI-12 master port for the radar level sensor and additional standard hydromet sensors, an RS-485 Modbus port for weather and water-quality probes, two isolated 4–20 mA current-loop inputs for legacy transducers, and a tipping-bucket digital input with hardware debounce and surge protection. Surface-mounted TVS arrays, common-mode chokes and isolation barriers protect every external interface against lightning-induced transients — essential for a pole standing alone on an exposed riverbank.

The top board is the IoT edge gateway, running Redcoast firmware that timestamps, validates and locally pre-processes every reading. The gateway evaluates rate-of-rise, multi-stage absolute thresholds and rainfall-intensity rules at the edge, triggers local outputs (siren/strobe relay, camera capture) within seconds, and uplinks compressed telemetry to Redcoast's cloud platform or any third-party SCADA/hydrology backend over MQTT or HTTPS. Bidirectional control lets operators reconfigure thresholds, sampling intervals and firmware over the air, so a national network can be retuned from a single dashboard.

Connectivity & Power

The station ships with a configurable radio bay supporting 4G LTE Cat-1/Cat-4 with auto-failover, NB-IoT Cat-NB2 for utility-grade low-bandwidth deployments, LoRaWAN for backhaul into customer-owned private gateways, and an Iridium short-burst-data option for true global coverage in roadless terrain. Public Wi-Fi is included for on-site maintenance and commissioning.

Power is delivered by a high-efficiency monocrystalline solar panel (60–200 W, sized to site insolation) charging a 50–200 Ah LiFePO4 battery via the Redcoast MPPT board. The system targets seven to fourteen days of full autonomy under worst-case insolation, with adaptive duty-cycling that reduces sampling and radio uptime in extended low-light conditions while still preserving alarm latency. Battery and panel current, voltage and temperature are continuously telemetered so that maintenance teams can prioritise visits by predicted health, not by calendar.

Protection & Reliability

The main cabinet is IP66; external sensor housings are IP67/IP68 where they sit close to water. The unit is rated for -30 °C to +60 °C ambient operating temperature, 0–100 % RH non-condensing, and is salt-spray tested for coastal and estuarine deployments. The pole or bridge bracket is hot-dip galvanized and finished with a smooth matte powder-coat or fluorocarbon paint system for long-term corrosion resistance in marine and high-UV climates. Designed service life of the LiFePO4 battery is 8+ years at typical hydromet duty cycles; the PCB stack carries conformal coating on every board and is engineered for a 10-year field life.

Application Scenarios

• River and stream gauging: Continuous water-level and rainfall telemetry for national hydrology networks, replacing legacy float-and-stilling-well gauges with low-maintenance non-contact radar.
• Flash-flood early warning in wadis and dry channels: Detects rapid rate-of-rise during sudden storms and triggers downstream sirens, VMS road-closure signs and SMS alerts before water reaches the road.
• Urban drainage and culvert monitoring: Tracks surcharge at critical culverts and stormwater outfalls, feeding city flood dashboards and traffic-management systems for real-time street-level response.
• Dam and reservoir telemetry: Headwater/tailwater level, spillway flow estimation and on-catchment rainfall delivered to dam operations centres for safe-yield and spill management.
• Bridge scour and overtopping monitoring: Bridge-mounted radar measures clearance to water and triggers closure thresholds for road authorities ahead of structural risk.
• Coastal and estuarine tide-gauge backup: Solar autonomy and Iridium failover keep the station alive when the grid and cellular networks go down during a storm event.

Case-style Examples

• Mountain flash-flood corridor: A network of twelve RC-FWS-200 stations was deployed along a 40 km mountain road prone to sudden debris-flow events. Radar level sensors at bridge crossings combine with upstream rain gauges; the edge gateway publishes a rate-of-rise alarm within 15 seconds, automatically triggering road-closure VMS boards further downstream and notifying the road authority's control room.
• Urban drainage retrofit: Twenty stations were installed across a metropolitan drainage network, each in a slim bridge-rail cabinet with a 60 W solar panel and NB-IoT backhaul. Operators receive culvert surcharge alerts in their existing SCADA, and several seasons of historical level/rainfall data are now being used to recalibrate the storm-water hydraulic model.
• Off-grid reservoir telemetry: A remote irrigation reservoir with no cellular coverage was instrumented with two RC-FWS-200 stations using Iridium SBD for daily telemetry and emergency alarm uplink, allowing the operator to manage controlled releases without sending field staff weekly to read a staff gauge.

Customization & Selection Guide

• Budget single-point gauging: RC-FWS-200 base with radar level + tipping-bucket rain gauge, 60 W solar, 50 Ah LiFePO4 and NB-IoT — suited for dense, low-bandwidth municipal networks where many gauges per district matter more than rich telemetry per gauge.
• Critical flash-flood crossing: Add the local siren/strobe pack, HD camera, dual-bearer 4G + Iridium, and upsize to 120 W solar / 100 Ah battery to guarantee alarm uplink during the very storm conditions that matter most.
• Multi-parameter hydrological station: Add SDI-12/RS-485 sensors for water quality (turbidity, pH, conductivity, dissolved oxygen) and a compact weather mast (wind, temperature, humidity, barometric pressure, solar radiation) to convert the unit into a full hydromet observatory.
• Harsh-environment variant: 316 stainless cabinet hardware, marine-grade fluorocarbon coating, extended -40 °C cold-pack battery option and an anti-vandal pole sleeve for high-corrosion or high-tamper sites.

Deployment & After-sales

Redcoast delivers each station as a pre-commissioned kit: pre-wired cabinet, pre-paired sensors, pre-loaded firmware and a clear deployment checklist. Typical site installation is half a day per station for a two-person crew — pole or bracket up, panel and antenna oriented, sensors aligned, station powered on, telemetry verified to the cloud. Engineering services include site survey, hydraulic threshold tuning, SCADA / hydrology-platform integration, operator training and a multi-year warranty with remote diagnostics. Spare-part kits (PCB stack, radio module, battery, sensors) are stocked for rapid mean-time-to-repair, and firmware is updated over the air.

Standards & Compliance

Designed to align with WMO rain-gauge measurement principles, IEC 60529 (IP66/IP67 enclosure ratings), IEC 61000-4 EMC immunity (including surge per IEC 61000-4-5), IEC 62133 for the battery system, and RoHS/REACH for materials. The product is CE-marked at the system level; FCC/IC and other regional radio variants are available for the cellular and LoRaWAN bays. Sensor data formats follow common hydromet conventions (SDI-12, Modbus RTU, JSON over MQTT) for direct ingestion into widely used hydrology platforms and customer SCADA.

Why Redcoast

Redcoast is not a reseller of off-the-shelf boxes. Every RC-FWS-200 is built on Redcoast-designed PCBs — the MPPT power board, the multi-channel signal-conditioning board and the IoT edge gateway — with firmware, mobile app and web platform also designed in-house. That means we can re-spin the signal-conditioning board to add a project-specific sensor, change the radio bay for a region-specific cellular band plan, adapt the cabinet for a harsh micro-environment, or integrate directly into a customer's existing SCADA or national hydrology backend. Software-hardware integration is end-to-end, and there is no third party standing between the buyer and the engineer who designed the board.

Contact Redcoast to discuss your flood-warning or hydrological monitoring network — share your site list, sensor mix and integration requirements, and our team will return a tailored configuration, deployment plan and price.