By Prashant Dhingra Use Cases & Industry
Using AI/ML to Estimate Waterflow When Sensors Fail
Saving Lives and Reducing Infrastructure Costs
Accurate, real-time waterflow data is crucial for emergency response teams to assess flood risk during storms and floods, but the current infrastructure for collecting this vital information is hindered by operational and financial obstacles.
The US government has allocated $20 billion for the installation of stream gages nationwide. Each gage has an estimated cost of $50,000, and there are annual operational expenses of $200 million to sustain the network.
Gauges frequently malfunction, especially during floods and storms when they are most necessary. The sensors are often damaged or destroyed by floating trees and debris in the river.
During flood and storm emergencies, emergency response teams require immediate access to waterflow data to identify at-risk areas. Unfortunately, gages are prone to failure or damage during these critical moments.
Gages are not suitable for predictive maintenance as they can fail unexpectedly in harsh conditions. The complex relationships between weather, snow, temperature, and dam operations make forecasting waterflow directly very challenging.
The issue lies not in predicting the failure of gauges or forecasting waterflow in isolation. Rather, it involves staying aware of waterflow levels even in the event of sensor malfunctions. The solution is to employ machine learning to approximate waterflow at non-functional gauges using data from nearby operational gauges.
We utilize machine learning to rely on connections between neighboring gages instead of forecasting gage failures or exact waterflow. By analyzing data from related gages in the vicinity, we can accurately estimate waterflow when a gage malfunctions.
Government agencies can still acquire highly accurate waterflow information, with a success rate of over 90%, even in cases where gages malfunction, ensuring the dependable data essential for making emergency response decisions.
Organizations can significantly reduce costs on emergency repairs and operational expenses by ensuring system visibility without depending solely on flawless sensor availability.
Emergency responders can use their knowledge to assess flood risk even in the absence of functioning sensors. When conditions are hazardous, there is no need for teams to endanger lives by replacing faulty gauges.
The solution doesn't necessitate the replacement or upkeep of all gages. It operates effectively with existing gages by making intelligent estimations to prevent failures.
In flood-prone regions like Alaska, where gages often fail during winter and storm seasons, teams can now avoid risking lives by using a reliable ML system to estimate waterflow. This enables emergency response decisions to be made even when gages are not functioning.
Creating a successful ML model hinges on recognizing the patterns present in your data. Straightforward patterns call for basic models, while intricate patterns call for more advanced techniques.
Data Characteristics: Clear, distinct patterns are visible
Requirements: Need less data, fewer features, simple models
Expected Outcome: Highly accurate results with straightforward approaches
Example: Strong seasonal waterflow patterns with clear peaks and valleys
Data Characteristics: Patterns exist but are subtle or multi-layered
Requirements: Need more historical data, additional features, complex models
Expected Outcome: Good accuracy with sophisticated modeling approaches
Example: Waterflow influenced by multiple correlated factors (weather, temperature, reservoir levels)
Data Characteristics: Patterns are highly complex or non-linear
Requirements: Different algorithms, many features, complex or deep learning models
Expected Outcome: Moderate accuracy::inherent complexity limits predictability
Example: Extreme events, unusual weather combinations with unprecedented impacts
The complexity of your patterns determines your approach. Begin by exploring your data before assuming that deep learning or intricate models are necessary. Simple, interpretable models can often uncover obvious patterns, while more complex ones may be needed for intricate patterns, but may have their limits in predictability. Make sure to understand your data thoroughly before selecting a model.
The ML model structure includes four key stages: collecting data and performing correlation analysis, training the model, managing flooding events, and making real-time predictions. This methodical process guarantees precision and dependability in critical situations.
Compute once per year: Examine stream data from NWIS to cluster gages with similar time series patterns, pinpointing gages with matching surge or decline trends in waterflow. Identify regions lacking clustering (possible coverage gaps).
Output: Gage clusters with strong correlations ready for modeling
Compute once per year: Develop machine learning models for each gage utilizing SHEM (Streamgage Hydrologic Estimate Using Machine Learning) to differentiate between easily predictable gages with strong correlations and more challenging gages with weak correlations in remote areas. Create reliability models based on past data and validate them across various datasets.
Output: Trained models with confidence scores for each gage
Real-time execution: If a stream gage malfunctions, locate operational gages within the same group. If necessary, update the model in real-time with new data to ensure forecasts adjust to present circumstances instead of just past trends.
Output: Adaptive models responsive to current conditions
On-demand execution: Forecast waterflow for malfunctioning gauges by utilizing operational gauges within the group. Obtain key findings on necessary enhancements or new components to enhance precision and coverage. Enhance the system continuously by evaluating prediction effectiveness.
Output: Real-time waterflow estimates for emergency response teams
The ML model shows different accuracy levels for different gages, with identifiable patterns that help explain why some locations are more predictable than others. Recognizing these patterns is key to enhancing the model further.
Performance: Excellent correlation between predicted and actual waterflow
Explanation: Strong geographic/hydrologic correlations with nearby gages enable accurate estimation
Characteristics: Gages with multiple similar neighbors in the cluster
Use Case: Safe to use for emergency response decisions
Performance: Accurate predictions for gradual changes, struggles with sharp declines
Explanation: Models capture general trends but miss rapid state changes
Characteristics: Normal conditions well-modeled, extreme events less accurate
Use Case: Use with caution during extreme weather; supplement with additional features
Performance: Moderate accuracy overall
Explanation: Insufficient training data, low correlations with nearby gages, or uncommon local conditions
Improvement Path: Candidate for deep learning approaches or additional feature engineering
Action Items: Gather additional historical data and uncover more predictive features such as weather, elevation, and vegetation.
Although the system may not be completely accurate on all gages, it still offers decision support for emergency teams. The system's high accuracy rate on predictable gages is beneficial for numerous critical locations. In instances where gages are difficult to predict, the system alerts teams to potential risks and uncertainties, allowing them to take necessary precautions. When paired with manual inspection, the machine learning estimates greatly enhance situational awareness during floods and storms.
Developing a predictive monitoring system involves a methodical process that integrates technical advancements, operational integration, and ongoing enhancements.
Gain insights from your data by examining historical waterflow patterns at each gage, identifying clusters of gages with similar patterns, and evaluating pattern complexity to determine the suitability of simple or complex models.
Apply time series similarity metrics for gage cluster identification, calculate correlations among gages in each cluster, and pinpoint areas of weak or absent clustering. Document the predictability of individual gages as either easy or challenging.
Begin with basic regression or time series models for simple gages that are easy to predict. Utilize more advanced models only when necessary due to the complexity of the data. Update models yearly using the complete historical dataset and test them on separate data to assess their real-world effectiveness.
Utilize emergency response systems to incorporate real-time waterflow estimates in the event of gage failure. Show confidence scores to assist teams in gauging reliability and establish alerts for when critical gages are not accessible. Conduct training for emergency response teams on utilizing these estimates.
Track the accuracy of predictions in real-world scenarios, pinpointing cases where errors occur systematically. Gather additional data to potentially enhance accuracy, continuously improving models. Extend analysis to challenging locations by collecting targeted data and refining features.
Start with Data Understanding: Don't assume you need complex models. Explore your data first.
Leverage Correlations: Geographic and hydrologic correlations are more predictable than absolute values.
Identify Easy vs Hard: Segment gages by predictability. Use simpler approaches where they work.
Build Iteratively: Begin by addressing 80% of locations, enhance to 90%, and then tackle the more challenging remaining cases.
Integrate Operationally: The top model is only beneficial when utilized by emergency responders.
Anticipatory monitoring for stream gauges provides significant benefits in financial, operational, and human aspects.
In a theoretical system containing 1000 gauges, approximately 10-15% encounter yearly failures, equating to around 100-150 gauges. Emergency replacement expenses amount to approximately $5-7.5 million annually, with each replacement costing around $50,000. The cost of developing a machine learning system for this scenario is estimated at around $2-3
Predictive monitoring demonstrates how ML solves real operational problems. The real challenge lies in staying alert to your surroundings even when sensors are not perfect. By using correlations between neighboring sensors, you can make accurate estimates of missing data.
The key to success is pragmatism. Begin by exploring the data to identify patterns, whether they are clear or subtle. Create basic models when possible, opting for more complex methods only when necessary. Collaborate with operations to ensure that predictions are effectively implemented.
The value is substantial and multifaceted. Cut expenses by preventing last-minute repairs. Enhance safety by avoiding risky sensor swaps. Boost emergency readiness with dependable data in crucial moments. And most importantly: protect lives by providing decision-makers with critical information.
Predictive monitoring isn't theoretical::it's practical, deployable, and impactful today. No matter if you are overseeing water systems, power grids, infrastructure networks, or any distributed monitoring system, these principles remain relevant. The key is to utilize machine learning to predict missing sensor data based on related data points, stay informed even during failures, and provide value when necessary.