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FlowWorks Welcomes FTS as a New Data Partner

Posted on August 26, 2011 by Timothy Hicks

FlowWorks is pleased to announce that users can now connect directly to Axiom™ data loggers made by FTS. Often used for hydrology, and a prominent in North American fire weather station networks where extreme duty is required, the touch-screen enabled Axiom loggers are well known for their rugged reliability and simplicity of operation. Users of FTS loggers can now access their data directly through FlowWorks using either GOES or Globalstar satellite telemetry. For the first time, users of this respected logger can access all the power of FlowWorks.

As an example, combining data from FTS Axiom data loggers with the extreme power of FACE, FlowWorks Advanced Calculation Engine, allows users to perform real-time calculations on any incoming data stream. The possibilities are nearly limitless, ranging from combining data at multiple locations into a single algebraic or logic equation, to writing complex alarming rules spanning entire networks. In addition, because FlowWorks is hardware-neutral, data from FTS equipment can easily be combined with data from any other data logger, SCADA system and USGS or NOAA station.

FlowWorks combines powerful graphing tools with robust analysis capabilities including I&I, rainfall IDF, CSO monitoring with multi-station alarming, and storage for all forms of metadata. The addition of FTS data allows FlowWorks clients the option to combine it with other monitoring data for a dramatically improved understanding of local conditions and how they affect water and sewer networks.

You can learn more about FlowWorks and our partnership with FTS here.

New FlowWorks Tool – Rainfall Mass Balance

Posted on April 20, 2011 by Craig Kipkie

FlowWorks is pleased to announce the arrival of our newest rainfall analysis tool. This one is aimed at easing the task of performing quality control checks when you have multiple rain gauges. It can be used to validate rainfall from both historical and current events, and like all FlowWorks tools it’s quick and easy to use. Check it out…

Tipping bucket rainfall gauges are prone to various sources of failure, including plugged funnels, seized bearings, sudden changes in instrument level, and even well-meaning staff who perform maintenance inspections without reporting when these were done. The result sometimes sticks out like a sore thumb, say months of missing data or sudden, inexplicably high “events”. But often, these problems are not clearly visible and can be missed. This is where our Rainfall Mass Balance (RMB) tool comes in.

Say you have two rain gauges in your network. If you want to check how one of them is doing, a good way to do this is to check it against the other. Although they probably won’t show the same values for a given period, it’s a good bet they will be reasonably well correlated if the gauges are close together. You could use our rainfall statistics tool to generate a monthly summary for each gauge to check their totals, or you could graph them together in our graphing system and use the summary table to see the totals that way. But now, there is an even better way, using the RMB tool. The RMB tool allows you to plot the cumulative rainfall total from one gauge against another, for any given time period that you want. Check out the simple example below, which shows the relationship between two rainfall gauges for the past 30 days:

As you can see, there is a pretty nice relationship between the two sites, indicating that both gauges were likely working well during this time. Now let’s look at an example where one of the gauges was not working during part of the period:

In that example, you can see that for a period while rain was continuing to be registered at the Surrey Kwantlen Park site, no new rain was being recorded at the Semiahmoo F&G rainfall station. The effect is even more pronounced if you choose to look at several rainfall gauges at once:

In the above example, two other gauges continue to record nicely during the time that the Semiahmoo F&G gauge is not operating, showing even more clearly where the problem lies.

Finally, you can choose to select the average of a group of gauges for use in X-axis of your graph. This lets you filter out the effects of any one station. Let’s take a look at this example:

You can see in the above example that we have chosen to combine the average of 3 separate rainfall gauges to use as the X-axis in our graph. This is great when you want to work with the average value over a larger area, rather than relying on a single gauge for comparisons.

When you are done, you can choose to print or export these graphs, and you can even save them as templates for future use!

FlowWorks: A True One-Stop Monitoring Shop

Posted on February 2, 2011 by Craig Kipkie

Flow monitoring must be efficient in order to truly be effective. With that in mind, FlowWorks continues to promote the ease of accessing all data sources in one location. We now have the ability to add real-time United States Geological Survey (USGS) and National Oceanic and Atmospheric Administration (NOAA) station data into our already- robust flow monitoring network.

The additional data is comprehensive:

Precipitation
Groundwater level
Streamflow
Surface water quality
Tide data

The upgrades bring more than 2,500 USGS precipitation stations, 9,000 streamflow stations, 1,300 groundwater level stations and 1,900 surface water quality stations to FlowWorks users. And, NOAA allows access to almost 50 real-time tide data streams. It’s all just keystrokes away. For a list of available stations in your area click here for USGS and here for NOAA.

This real-time data is typically recorded at 15- to 60-minute intervals, stored onsite, and then transmitted to USGS offices every one to four hours, depending on the data relay technique used. Recording and transmission times may be more frequent during critical events. Plus, data from real-time sites are relayed to USGS offices via satellite, telephone, and/or radio telemetry and are available for viewing within minutes of arrival.

The benefits are impressive. In essence, FlowWorks analysis and reporting tools enable more useful information to be captured from the USGS stations. For example, clients are able to enhance their existing rain gauge network with all available stations in their monitoring area, which increases access to spatial and temporal storm information.

Gwinnett County in Georgia is using this service to bring the 18 local USGS rainfall stations into their FlowWorks platform in addition to the 12 rainfall stations coming in from their SCADA system. The result will be a dramatic improvement in their understanding of local rainfall conditions.

Implementing these new features—additional data—from FlowWorks requires just a small one-time setup fee and no monthly charges. More importantly, accessing all your data in one spot, and in real time, will improve the decision-making process perhaps more than any other upgrade a firm could make.

Troubleshoot Your Rain Gauge – Is it Plugged?

Posted on February 1, 2010 by Yasemin Parkinson

water bucket

I have been doing QA/QC on hydrometric data for many years, and as part of my job I ensure that data being collected is as accurate as possible. This extends to the instruments collecting the data – today I’m going to talk about troubleshooting a tipping bucket rain gauge, and some of the tools I use within FlowWorks to do so.

If you use a tipping bucket rain gauge you may notice that from time to time the funnel can become clogged with dirt, mud, leaves and other forms of debris. Clearly a plugged rain gauge will not collect accurate rainfall or precipitation data!

The key is to be able to quickly identify a plugged rain gauge so it can be cleaned out without delay. There are two ways to do this – accessing your online data (like you could if you are a subscriber to FlowWorks), or manually checking the unit in the field. I’m going to review both of these options in this article.

Identifying A Plugged Rain Gauge Through Data Analysis

Identifying a plugged rain gauge can be easy when you know what to look for and if you have access to right analysis tools. If you are lucky enough to be receiving live data, you will be able to identify a plugged rain gauge as often as you check the data. Historical data is ok too because you will at least be able to identify data sets where the rain gauge was plugged and make sure to disregard that data during further analysis.

A Completely Plugged Rain Gauge

You can tell a rain gauge is completely plugged when there is no rainfall data being recorded when you clearly know that is raining. So if you are looking outside your window and its pouring rain and your live rain gauge isn’t showing any rainfall data, it is probably safe to assume that it’s plugged. Or if you can compare the data to another rain gauge in the same area they should show similar rainfall.

single rain gauge data

Partially Plugged Rain Gauge

Sometimes a rain gauge is only partially plugged. If this is what has occurred then you would see ‘weird’ rainfall patterns. That is because during rainfall the gauge will start to fill with water and then the water will start to slowly trickle trough which looks like constant low rainfall and it will tend to continue long after the rainfall has stopped.

In the figure below, the data from two rain gauges located in close proximity are graphed using the FlowWorks graphing tool. The two rain gauges should show similar rainfall but during the last week of August 2008 the bottom rain gauge became partially plugged. The constant slow filtering of the rainfall is quite obvious and this is a common indicator that the rain gauge is plugged.

double rain gauge data

Identifying A Plugged Rain Gauge Through Inspection

The other way to check if a rain gauge is plugged is by pulling it apart on a site visit. You will either see the funnel clearly plugged or the collection cylinder may be full of water and not draining. Remove the cylinder to drain the water and make sure the funnel is completely clear of debris. If the cylinder is not full of water but you still have suspicion that it is plugged, you can pour some water slowly into the cylinder and if the water does not drain or drains very slowly then there may be a partial plug.

IDF Curves Explained

Posted on December 10, 2009 by Craig Kipkie

flood

Here in the Pacific Northwest it has been raining almost everyday this month. The rain gauge station closest to my house has recorded over 550 mm (22 inches) for November, which is considerably above average.

We have had several storms during this period, but very little flooding issues. My neighbour and I were talking last week after one of the storms and he commented how much it rained the previous night (the local rain gauge measured 27 mm). I agreed with him that it did seem like a good one, but later that afternoon I did a quick analysis using FlowWorks’ Intensity- Duration- Frequency Analysis tool and it turned out that the storm wasn’t “significant”.

So, what constitutes a significant rainfall event and how did I used the IDF analysis tool to quickly determine the severity of the storm?

The basics: What is an IDF Curve?

Here’s the simple answer: An IDF curve tells you how rare a given rain storm is. Take that storm I looked up from the other night. It is intuitive to understand the idea of how many mm or inches of rain falls. It’s not quite as easy to say how often that storm might occur? Every 1 year? 2 years? Maybe it was a 1-in-10 year event? An IDF curves helps to quantify that, so you can actually say to your neighbour over the fence, yeah, it seemed like a lot of rain but really we get a storm or two like that every November.

I’ve oversimplified it, but that’s ok. Read on for a more detailed explanation.

The Official Definition of an IDF Curve

An Intensity-Duration-Frequency curve (IDF Curve) is a graphical representation of the probability that a given average rainfall intensity will occur (yeah, what a mouthfull!)

Rainfall Intensity (mm/hr), Rainfall Duration (how many hours it rained at that intensity) and Rainfall Frequency (how often that rain storm repeats itself) are the parameters that make up the axes of the graph of IDF curve. An IDF curve is created with long term rainfall records collected at a rainfall monitoring station. I’ll get into the details of how a to create an IDF curve and how much data you need in a future post, but needless to say, you need a lot of data. And the more data you have, the more accurate your curve will be.

How to Interpret an IDF Curve

Rainfall intensity in the IDF Curve is the average rainfall depth that falls per specific time duration. Simplified, high rainfall intensity indicates that it’s raining really hard and low intensity that it’s raining lightly. Typically the rainfall intensity is stated in mm/hr in Canada and in inches/hour in the United States.

IDF curve

Take a look at the graph above. The y-axis shown the rainfall Intensity in mm/hr, and the x-axis shows the rainfall Duration. There’s the I and D” in the IDF.

The nearly parallel lines on the IDF Curve represent probability, or Frequency (yes, the “F” in the IDF). So the 10-year line would represent rainfall events that have a probability of occurring once every 10 years. Another way to put it is that the probability of a 10-year magnitude storm (or greater) occurring in any given year is 1/10 or 10%, and of a 50-year storm occurring 1/50 or 2%. I should note that the information presented in the graph is based on statistical analysis of past data, rather than a prediction of actual storms.

Each plotted line in the graph represents rainfall events with the same probability of occurrence, in a range of durations (durations are shown on the x-axis). A 10-year storm can therefore be of any duration – a 10-year 30-min storm, a 10-year 2-hour storm or a 10-year 12-hour storm.

Finally, the last line on the curve is the actual rainfall event, based on the data collected from the local rain gauge. In this case it falls below all the parallel lines. Where (and if) the line crosses any of the parallel probability lines, would represent the actual Intensity, Duration, and Frequency of the storm.

Where Can you Find an IDF Curve?

IDF curves are available for many locations in Canada, produced by the Environment Canada’s Meteorological Service of Canada (formerly Atmospheric Environment Service). They are updated periodically, many as recently as 2005, and are available for free download from their FTP site.

A different system of illustrating rainfall statistics exists in the United States. Areas of same statistical rainfall depths are mapped for specific return periods and storm durations. There iso-hyetal maps are called TP40s (Technical Paper No. 40) and can be found for free download on the US National Weather Service. These links are great starting points for understanding rainfall behaviour in different areas of the US or Canada. Local or specialized agencies may have their own rainfall statistics that more closely emulate local conditions and experience, or particular uses for the rainfall information. Examples of these agencies include state/provincial transportation departments, municipalities, environmental protection agencies, etc.

FlowWorks and IDF Curves

FlowWorks can provide you with a quick severity analysis for a storm event.

Did the rain that fell yesterday meet or exceed the 10-year storm? Do you need to report to your City Council the possible reasons why flooding occurred during today’s big storm event? FlowWorks has a tool that can easily answer those questions. By linking your rainfall station to FlowWorks and using our Rainfall Analysis Tool you can plot the storm event as it occurs on the station’s IDF Curve in a matter of seconds. Many of you have likely gone through this exercise using a spreadsheet and found it to be cumbersome and time consuming. The analysis can be redone instantly as new data appears in the database. I have many clients who will “watch” a storm event as it rolls in from the comfort of their desk and send out their operations crews as a storm event hits a certain severity rating to areas where they know that may have issues.

The analysis can also be easily done on all the historical data in your database. The example graph below shows that rainfall that fell near the District of North Vancouver’s rain gauge August 13, 2009 exceeded the 1 in 10-year event for short duration storms (5-15 minutes) and exceeded the 2-year event for a 2-hour storm.

IDF curve

If you’re interested sign up for a free online demo where we can take you through the process of integrating your existing data and climate stations into the FlowWorks system. Want to know more? Stay tuned for my upcoming articles on “How to Create an IDF curve”, and “What are the other uses for IDF Curves”.

Data Loggers for Remote Data Collection Systems: Which One to Choose?

Posted on November 30, 2009 by Jason Vine

cassette tape

I am a practising Professional Egineer who does A LOT of data collection applications, both for my clients as well as for the 150 or so employee needs within my own firm. When someone asks me what kind of data logger they should use, I always start by asking them where the data logger will be located, and what it will be used for. There are plenty of choices! Here’s a few of the systems and applications that are currently connected to FlowWorks.

Telog

We have some small water and sewer treatment plants that talk to FlowWorks using Telog’s wireless 1XRTT modem. We like the Telog products (particularly the 3307 and 3314), as these units are very reliable and they have some very flexible telemetry options (including dialup phone, wireless, and direct Ethernet connections).

ISCO

ISCO 2150 area-velocity meters in sanitary sewers come in via ISCO’s wireless 1XRTT system. The ISCO’s are purpose-built and hence not as flexible as the Telog wireless system, but the ISCO’s are compact units that generally get the job done well enough.

Marsh McBirney

There are a few Marsh McBirney FloDar’s connected to FlowWorks. These units were plugged into the Telog RU33 product, which acts as a data recording and telemetry module for the FloDar.

There is an ADS FlowShark connected to FlowWorks. We don’t have a lot of experience with these yet, but our client out East seems to be happy enough with the unit. It uses wireless 1XRTT just like the Telog and ISCO systems.

Satellite Stations

We have remote stations that use satellite because there is no other option where these sites are located. Right now we have Campbell Scientific and Unidata Neon systems connected. We know that Campbell Scientific systems have been around for a long time and have a proven track record. The Neons also seem to be holding up well.

The bottom line is that there are several ways you can do any particular data collection application. We are always doing new applications, and we keep on top of what’s out there on the market, what works well and what doesn’t. Feel free to ask us for a bit of advice the next time you are looking to do a new data collection application! We work with an expanding list of logger manufacturers, and we provide unbiased advice.