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A Fixed Downstream Flow Monitor and Rain Gauge

Rain, snow melt, and their effects are a cause of concern for most collection systems. Understanding how intermittent wet weather events affect sanitary flows gives utility owners insight when dealing with the severity of clear water inflow or infiltration. Since permitted plants are required to track the daily gallons of treated flow, as well as daily precipitation, rethinking how to collect and analyze this data offers an inexpensive benchmark when monitoring a clear water separation program.

For small systems, FloCis recognizes that tracking rain rate patterns should start at the treatment plant. Measuring rain in near real time by use of a tipping bucket type gauge (instead of the traditional method of total rain amount each 24 hours) creates a more accurate correlation with the interval flow data collected at treatment plants. An electrical signal from a Chart Recorder Image of a tipping bucket rain gaugeidentifies the gallon flow amount over time. Typically, plant operations are only concerned with daily total flows for required regulatory reporting. However, taking that same Chart Recorder and electronically tying it to a PLC (programmable logic controller) allows a desktop computer to store and organize the real time flow data. (The PLC collects and converts the chart recorder data and then sends it to a desktop.)

In addition, a tipping bucket rain gauge and data station records are totaled along with rain rate information and a time stamp. (This is a 2-bucket funneled device that can measure a .001th inch of precipitation. With a seesaw effect, as each .001th inch fills the bucket, it tips. The data collector then records the time of each tip.) Adding the tipping bucket rain gauge data to the desktop computer in a common database then completes the data collection process. A simple mathematical algorithm then synchronizes the plan or lift station flow rate with the rain or snow melt rate.

Using the processed data effectively is the next step. Plotting the two data sets will then visually correlate rain rate and flow. Having historical data that charts rain rates and the flow patterns will then enable system personnel to predict flows and make preparations for handling large peaks. In addition, these patterns can reveal progress made when improving the collection system, as well as predicting when SSO or CSO events are likely to occur.

While treatment plants have been designed and operated to take as much flow as possible, there are consequences when overflows occur. Affordable tools that can help avoid regulatory infractions and document progress being made are what communities need. FloCis is committed to developing and refining this type of analytical tool.