Tag Archives: Groundwater monitoring

FlowWorks Now Links Directly to USGS & NOAA Data

Posted on by

FlowWorks can now accept real-time data directly from United States Geological Survey (USGS) and National Oceanic and Atmospheric Administration (NOAA) monitoring stations.

For the first time ever, utilities, municipalities, and industrial clients can access this valuable data directly through FlowWorks to enhance understanding of their regional environment.

The addition of the USGS and NOAA data means over 2,500 precipitation stations, 9,000 stream flow stations, 1,300 groundwater level stations and 1,900 surface water quality stations and nearly 50 tide stations are now available to FlowWorks clients in real time.

Clients can use the new data to augment local networks, or simply as a means of cross-checking local monitoring results.  For example, enhancing an existing rain gauge network with local USGS rainfall stations will increase spatial and temporal storm information and improve correlation with observations on the ground.  FlowWorks stores all data in a single massive database so it can be analyzed quickly, understood and the results communicated to all users.  It’s now just keystrokes away and the benefits are impressive.

You can read more about using FlowWorks with USGS and NOAA data here.

FlowWorks: A True One-Stop Monitoring Shop

Posted on by
Reply

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.

Inflow and Infiltration 101 – Part 3

Posted on by
Reply

This is part 3 of Mike Homenuke’s series on Inflow and Infiltration. For part 1 click here and part 2 click here.

Why care about I&I?

 Before we get too much further into this, we should probably discuss why we should even care about inflow and infiltration into our sanitary sewers. Whether you’re an engineer or an urban planner, inflow and infiltration (I&I)—surface runoff and groundwater that has entered the sanitary sewer system—should be on your radar.

 Sanitary sewer systems are designed to carry a specific volume of wastewater, usually from systems including toilets and sinks in homes and businesses. Meanwhile, stormwater sewers are designed to carry rainwater and groundwater away. However, when this water flows into sanitary sewers, it taxes the load on the overall system, including wastewater treatment plants.

 The result—public health risk and extra costs to your community. And if that doesn’t get your attention, consider that sanitary sewer overflows can kill fish and will violate state and federal environmental regulations.

 

Extra Load and Dangerous Consequences

Wet weather and storm events can quickly fill sanitary sewer systems beyond capacity. At that point, wastewater flows at higher-than-usual water levels and can begin to flood basements and homes and spill onto streets. These wastewaters and potential pathogens are a significant public health risk. And, as these flows mix into water bodies like streams and lakes, contamination becomes a major issue for all those interconnected waterways—harming the flora and fauna that reside there and can prompt officials to issue beach advisories and closures.

 EPA regulations 

The Environmental Protection Agency (EPA) requires regulated agencies possessing a National Pollutant Discharge Elimination System (NPDES) permit to stop all wastewater overflows from reaching United States waters. It’s a daunting and nearly impossible task because I&I can’t be stopped altogether, and will continue to increase over time as the infrastructure ages. Since the late 1980s public awareness and interest has grown in upgrading sanitary sewer infrastructure and municipalities are continuing to respond.

Costs can be high when it comes to dealing with I&I, and encompass fees associated with overflows, wastewater treatment and transportation facilities and funding opportunities. Also bear in mind that sewer backups that spill water into households can result in litigation for which the city or local agency may be responsible.

The best thing municipalities can do is to understand the I&I within their systems, and determine if larger responses could result in a problem.  I&I events are based on climatic events and as such their return periods can be calculated.  A return period I&I response that causes a sewer backup or overflow can be calculated for every pipe in a city. If the return period is less than the expected service level promised to the rate payers or results in an overflow that harms the aquatic environment, action is required.  Since I&I increases with sewer age, it’s important for utilities to understand the current response and calculate the corresponding return period.  Information such as this helps to avoid overflows and resulting fines—and starts with effective monitoring tools.

 Stay tuned for our next blog about how to quantify I&I and how FlowWorks can help.

Inflow and Infiltration 101 – Part 2

Posted on by
Reply

This is part 2 of Mike Homenuke’s series on Inflow and Infiltration. For part 1 click here.

Lets take a closer look  at the components that comprise I&I:

 Groundwater Infiltration (GWI)

These rates in the Pacific Northwest typically occur in the 3,000 – 5,000 L/ha/d range. High GWI can be found in:

  • Catchments with poorly draining soils
  • Deep sewers
  • Structural decay
  • Ungasketed joints 

 Achieving complete I&I reduction in these catchments will likely require an intense focus on rehabilitation of the lower portions of the system.

 Stormwater Inflow (SWI)

SWI usually results from:

  • Directly connected roof leaders
  • Foundation drains
  • Sump pumps
  • Catch basins
  • Defective sewer access points including manhole frames and covers, cleanouts and inspection chambers

SWI is indicated in flow monitoring records as sharp responses to rainfall events during summer months, but is nearly impossible to separate from Rainfall-Induced Infiltration (RII) during winter months. This can be quantified at a return period using the I&I Envelope Method.

Rainfall-Induced Infiltration (RII)

RII enters the sewer system through:

  • Leaking joints
  • Structural defects in pipes and manholes

Service connections are typically buried at shallow depths and are easily damaged. Additionally, brick risers and other component interfaces in manholes are not typically sealed. This allows for rapid infiltration of groundwater to occur. 

Infiltration in pipes and lower portions of manholes occurs more slowly, but can be significant during longer wet weather events.

It’s difficult to visually detect RII Because CCTV inspections are usually conducted during dry weather to prevent submergence of the camera. RII becomes fully developed when soils surrounding the sanitary sewer become saturated. This is also determined using the I&I Envelope Method, indicated by flow events with the highest ratio of Rainfall-Dependent Inflow & Infiltration (RDII) to rainfall.

Inflow and Infiltration 101 – Part 1

Posted on by
2

Today FlowWorks welcomes Mike Homenuke, GIS-based municipal infrastructure analysis and planning expert, to contribute Inflow and Infiltration (I&I) insight to the blog. An eight-year veteran of Kerr Wood Leidal Associates Ltd. (KWL)—a FlowWorks partner firm—Mike is a professional engineer who specializes in sanitary sewer systems and energy resources. His recent work includes development of sewer system hydraulic models, capital plans, sewer rehabilitation and I&I reduction programs, electrical generation resource planning and district energy planning. Mike’s current focus includes developing GIS solutions for engineering applications, including sewer asset management, district energy and web-based GIS.

Mike has a rich background in I&I management and sewer rehabilitation. Among highlights, he has reviewed and updated I&I for the Regional District of Kootenay-Boundary inceptor sewer system, has developed a new data model for storage and organization, and has completed an audit of an eight-year sewer inspection and rehabilitation program in the City of White Rock, BC.

Here’s part 1 of what he had to share regarding I&I:

Understanding Inflow and Infiltration (I&I)

Inflow and infiltration (I&I) is surface runoff and groundwater that has entered the sanitary sewer system. There are a number of ways these waters can enter the sewer system—and each pathway has particular characteristics that are described with a flow hydrograph.

The first step in reducing I&I is to understand its source.

This table is a great resource as it outlines the various components that comprise sanitary and I&I flows:

Table 1: Sanitary Flow Components

Component

Acronym

Calculated As

Definition / Explanation
Sanitary Flow
Average Dry Weather Flow ADWF Average daily flow measured during periods of dry weather (i.e. June to September). This includes both BSF and summer GWI.
Peak Wet Weather Flow PWWFRP Peak flow recorded during storm event, or modelled as peak sanitary flow on peak I&I.
Base Sanitary Flow or Average Domestic Flow BSF or ADF Average daily sanitary flows originating from domestic and industrial sources.
Peak Sanitary Flow or Peak Domestic Flow PSF or PDF BSF x peaking factor Peak hourly sanitary flow originating from domestic and industrial sources.
Inflow and Infiltration
Groundwater Infiltration GWI 85% of min. DWF Extraneous flow from the ambient long-term water table, not influenced by individual rainfall events.
Rainfall-Induced Infiltration RIIRP Rainfall that follows a path to the sewer through the soil and/or from short-term, rainfall-based increases in water table elevation. Identifiable in two components, slow and fast.
Stormwater Inflow SWIRP Rainwater that enters the sewer through direct (non-soil) connections to the runoff surface.
Rainfall-Dependant Inflow & Infiltration RDIIRP SWIRP + RIIRP Total peak rainfall-sourced extraneous flow, averaged over short-terms ranging from 5 minutes to 24 hours depending on catchment characteristics.
Total I&I I&IRP RDIIRP + GWI Total peak rainfall-sourced plus ambient extraneous flow, averaged over short terms.
RP=Return Period.  All of the rainfall-related parameters must be expressed with a return period if they have been derived from flow data or have been estimated with a hydrologic model.  It may be appropriate to express the return period as ‘major event’ in some cases.