Patent Application
20210340749
Stormwater infrastructure best management practices (BMP) are designed using accepted industry standards applied in individual states through state regulations and technical standards and are modeled and designed using source loading and management modeling (SLAMM) software. BMPs are generally recognized as structural, vegetative and/or managerial practices used to treat, prevent, or reduce water pollution from stormwater runoff.
BMPs can be thought of more simply using the conceptual diagram shown in
BMP design guidance is typically very conservative. For example, Wisconsin's technical standards for evaluating a site for infiltration provides three options for estimating infiltration rate at a site slated for future best management practice (BMP) installation (see https://dnr.wi.gov/topic/stormwater/documents/1002SiteEvalForInfiltr.pdf). Option 1 recommends digging a soil pit to evaluate the types of soils present at the site. The engineer must then select a standard infiltration rate based on published test results in the literature corresponding to the least permeable layer discovered in the pit. Option 2 allows infiltration to be measured directly using a double-ring infiltrometer test. This is better than Option 1 but is only representative of the location/day/time/conditions present when the test was conducted. In short, one set of double-ring tests define the subgrade infiltration rate used in the design of the BMP for the entire life of a BMP (intended to be in service 10-20 years minimum). Option 3 is essentially Option 1 with a correction factor (of less than 1) applied to the standard, published infiltration rates to account for compacted soil if efforts were not taken to mitigate such compaction during construction. These estimations typically prove very conservative and inaccurate.
Permeable pavement and biofiltration basins are BMPs which serve as filters capturing pollutants from stormwater runoff passing through their surfaces and their underground media and can be represented by BMP 200 shown in
Drawdown time is an important consideration when designing infiltration-type BMPs and can vary by jurisdictions. In Minnesota, for example, drawdown time is typically 48 hours, while it is 72 hours in Wisconsin. Each state or water jurisdiction may have similar or different drawdown times. There are several reasons infiltration-type BMPs must drain within an established time period including: (1) wet-dry cycling of the storage gallery; (2) minimizing the opportunity for mosquito breeding; (3) promoting suitable habitat for vegetation (bioswales); (4) promoting aerobic conditions (bioswales); and (5) ensuring storage capacity is available for the next rain event. See https://stormwater.pca.state.mn.us/index.php/Assessing_the_performance_of_infiltration
Known software packages like WinSLAMM (www.winslamm.com) conveniently allow engineers to input all these properties to evaluate resulting BMP efficiencies. WinSLAMM was developed to computerize the source loading and management modeling required to quantify the amount of pollutant captured by BMPs. At the time of this patent application, WinSLAMM is an approved model in Delaware, Georgia, Minnesota, New York and Wisconsin and it is referenced by stormwater design manuals in 16 other states across the US.
WinSLAMM documentation describes three mechanisms by which a BMP, like permeable pavement, can remove pollutants carried by stormwater (see http://winslamm.com/docs/WinSLAMM %20Model %20Algorithms %20v7.pdf). Stormwater is first filtered through the surface and bedding layers in the top portions of the pavement section removing larger-sized particles. The second pollutant removal mechanism is settling and can only occur if the stormwater is allowed to pond within a BMP. As water ponds inside a BMP, particles can begin to settle out at the bottom of the storage gallery. The third mechanism is through infiltration of stormwater directly into the subgrade beneath a BMP.
There is a tension when designing infiltration-type BMPs between infiltrating all water such that a 100% pollutant removal credit for every drop of stormwater runoff entering these systems is achieved with managing the risks of failure outlined previously due to failure to drain in advance of the next event. Engineers must consider both pollutant removal efficiency and drawdown time when designing infiltration-type BMPs. Often, pollutant removal efficiency is sacrificed to mitigate risk of failure. If an infiltration-type BMP is constructed without an underdrain near the bottom of the storage gallery, there is a chance stormwater runoff will not drain within the specified drawdown period. If this happens, the BMP is considered failed and must be reconstructed with an underdrain to receive pollutant removal credits. This may result in additional infrastructure spending and inefficiencies.
Thus, there is a need in the art to provide a system to maximize pollutant removal mechanisms to the greatest extent possible by sizing and locating underdrains within storage galleries such that stormwater is ponded for the full drawdown period after every rain event, with infrastructure which provides the necessary drainage features, but also does not require an increase in labor or active management of such BMPs. Moreover, there is also a need in the art to obtain information and display information which allows operators to monitor the functionality and performance of these BMPs to capture the necessary data to show compliance with federal and local regulations as well as demonstrate the efficiencies obtained.
This patent describes the utility of an invention that maximizes the efficiency of stormwater BMPs using internet of things (IoT) and real time control (RTC) technologies. The invention is described within the context of a permeable pavement BMP system, but is equally applicable to other stormwater BMPs like bioswales, underground infiltration basins, wet ponds, dry ponds, underground storage cisterns, green/blue roof systems, or any stormwater management system that could benefit from monitoring performance and actively controlling effluent discharge to increase system efficiency.
The present invention is directed toward an active water storage infrastructure management facility that includes a stormwater BMP comprising a storage gallery for containing a volume of stormwater runoff, a drain system in fluid communication with the storage gallery, a liquid level sensor disposed in the storage gallery for measuring the volume of runoff water introduced into the storage gallery, a fluid flow sensor disposed on the drain system to measure a portion of the volume of runoff water exiting the drain system, and a real-time-control valve disposed proximate an outlet end of the drain system. In one embodiment, the real-time-control valve is moveable between an open position and a closed position, and when the real-time-control valve is in a closed position, no runoff water exits the drain system and wherein when the real-time-control valve is in an open position, the portion of the volume of runoff water exits the drain system.
One embodiment may include a control system in electronic communication with the liquid level sensor, the fluid-flow sensor, and the real-time-control valve. One embodiment may include the drain system being an underdrain. In one embodiment, the BMP includes permeable pavement, and the storage gallery is an aggregate sub-base.
In another embodiment, an active water storage infrastructure management facility operating system may comprise a permeable pavement surface, a permeable base material disposed under the permeable pavement surface, a underdrain system comprising a plurality of individual drain lines and having at least one outflow point, a control system for managing the operations of the water storage infrastructure, a plurality of sensors for measuring one or more operating parameter, wherein the sensors disposed in the underdrain system, and each of the plurality of sensors in electronic communication with the control system. They facility may further include at least one outflow valve disposed at the outflow point, wherein the outflow valve may be in electronic communication with the control system, and wherein the control system may operate the outflow valve based upon the measurements of one or more of the plurality of sensors.
The present invention may also include a method for using the active water storage infrastructure management facility that includes the steps of: measuring a volume of stormwater runoff introduced into a storage gallery of a BMP due to a precipitation event using at least a fluid level sensor disposed in the storage gallery, measuring a first portion of the volume of stormwater runoff that is removed from the storage gallery through a drain system in fluid communication with the storage gallery using at least one fluid flow sensor disposed on the drain system, and determining a second portion of the volume of stormwater runoff that is either maintained in the storage gallery or permeates through a subgrade adjacent to the storage gallery.
The method may also include the step of controlling an outflow of the drain system to control the second portion of the volume of stormwater runoff to optimize an operation of the BMP to meet one or more stormwater runoff compliance parameters. One embodiment of the method may also include the step of maintaining a maximum draw-down time of the storage gallery through controlling the outflow of the drain system.
In another embodiment, the method may include measuring a contained volume of runoff within the storage gallery using at least a fluid level sensor disposed in the storage gallery, obtaining a weather precipitation forecast, wherein the outflow of the drain system is controlled in real-time based upon the measurement of the contained volume of stormwater in the storage gallery and the weather precipitation forecast. In another embodiment, the method may include the step of maintaining a maximum draw-down time of the storage gallery through controlling the outflow of the drain system.
In another embodiment, the method may include determining the amount of one or more pollutants, which are removed by the stormwater BMP using the determined first portion of the volume of stormwater runoff and determining the amount of the one or more pollutants removed by the stormwater BMP through infiltration through a subgrade of the BMP using the determined second portion of the volume of stormwater runoff. This embodiment may further include controlling an outflow of the drain system to control the volume of stormwater runoff in the storage gallery to optimize the amount of the one or more pollutants which are removed by the stormwater BMP through infiltration through the subgrade of the BMP. Further, this embodiment may further include maintaining a maximum draw-down time of the storage gallery through controlling the outflow of the drain system.
The method of operating the active water storage infrastructure management facility may also include the steps of measuring a contained volume of runoff within the storage gallery using at least a fluid level sensor disposed in the storage gallery, and obtaining a weather precipitation forecast, wherein the outflow of the drain system is controlled in real-time based upon the measurement of the contained volume of stormwater in the storage gallery and the weather precipitation forecast.
The present invention also includes a method for presenting information to a user of a system for monitoring stormwater infrastructure efficiency and progress related to EPA compliance comprising the steps of calculating a modeled data point of one or more infrastructure performance elements of one or more stormwater infrastructure elements, measuring a value of actual performance of the one or more infrastructure performance elements of the one or more stormwater infrastructure elements, and displaying a comparison of the modeled data point and the value of actual performance in a graphical format.
Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.
The accompanying drawings form a part of the specification and are to be read in conjunction therewith, in which like reference numerals are employed to indicate like or similar parts in various views.
The following detailed description of the present invention references the accompanying drawing figures that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the present invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the spirit of the scope of the present invention. The present invention is defined by the appended claims and, therefore, the description is not to be taken in a limiting sense and shall not limit the scope of the equivalents to which such claims are entitled.
The present invention is directed toward a system that maximizes the efficiency of stormwater BMPs using internet of things (IoT) and real time control (RTC) technologies. The invention is described within the context of one embodiment being a permeable pavement BMP system, but is equally applicable to other stormwater BMPs like bioswales, underground infiltration basins, wet ponds, dry ponds, underground storage cisterns, green/blue roof systems or any stormwater management system that could benefit from monitoring performance and actively controlling effluent discharge to increase system efficiency.
BMP system 10 may also include one or more antenna(s) 42 which connect system 10 to the computer, one or more sensors and/or controls which connect BMP system 10 to the cloud for the transmission and receipt of data through the internet. Antenna 42 may be one or more of a cellular, Wi-Fi, Bluetooth, satellite, or LoRa, or any future similar technology. In some embodiments, multiple communication technologies such as cellular, Wi-Fi, Bluetooth, satellite, or LoRa, may be incorporated into the system 10. For example, computer 36 may be connected to one or more sensors or controls via Bluetooth, and computer 36 may be connected to the cloud for data transmission and/or back up via a wireless cellular connection. Alternatively, BMP system 10 may be hardwired to the internet for hard-wired data transfer at the site.
BMP system 10 may also include one or more water-tight enclosures 44 for electronics, computers and antennas or other electrical components. The BMP system 10 may also include water-tight cables and terminations/connectors 46. The components of BMP system 10 may utilize a number of known terminations/connectors and infrastructure elements and mounting hardware, such as concrete pavers, steel brackets, steel poles, concrete foundations, perforated PVC sensor shells, etc., to mount and secure the components of BMP system 10.
While underdrains 14 do not make up a large portion of the cost of a BMP (if they are installed during original construction), they do affect a BMP's ability to reduce pollutants, which drives up the cost per pound of pollutant removed. BMPs capable of infiltrating all stormwater passing through them remove 100% of pollutants carried by runoff. Stormwater filtered through a BMP, then discharged through an underdrain reduces only a portion of the pollutants carried by the runoff allowing some pollutants to escape the BMP and to enter the public waters of the drainage system. Water discharged through permeable pavement underdrain is assumed to remove somewhere near 65% of total suspended solids (TSS) and 35% of total phosphorus (TP)—both significantly less than 100% achieved through a full infiltration system.
The size (diameter), location and number of underdrains 14 are important when designing a BMP system 10. All three factors help to determine how quickly BMP system 10 will empty after water enters the system. A large underdrain 14 at the bottom of a storage gallery 54 will provide an easy flow path for water to exit the BMP, limiting the ability for stormwater to be stored (ponded) in the storage gallery 54 and/or infiltrate into the subgrade 28. Raising the underdrain 14 to a higher elevation, shrinking the size, or reducing the number of underdrains 14 used within the storage gallery 54 all help to promote ponding and infiltration thereby increasing BMP pollutant removal efficiency. By doing this, however, there is increased risk that the BMP 10 will not drain within the specified drawdown time. If underdrain 14 is not installed within the cross-section of the BMP 10, observation wells are required to be installed to allow water level monitoring from the surface. Some state regulations require the observation wells be visited at least once per year at the drawdown time after a rain event of 0.5 inches or more to verify the storage aggregate is draining effectively.
When designing the present BMP system 10, designers recognize that when it rains, stormwater begins to run off surrounding area and drain to a BMP 10. When it reaches the BMP 10, the water permeates through its surface 12 and percolates into the storage gallery 54. The stormwater can then either infiltrate into the subgrade 28 beneath the storage gallery 54 or exit through an underdrain 14. As described previously, BMPs with underdrains 14 at the bottom of their galleries do not provide much opportunity for stormwater to infiltrate because the underdrain 14 provides a much easier path for the water to take out of the storage gallery 54. When analyzing a BMP, engineers quantify the total volume of stormwater runoff, VT, the portion of total volume infiltrated into subgrade, Vinf, the portion of total volume discharged through underdrain, VU, and the portion of the total volume that will bypass the system altogether (e.g. due to overflow), VB.
V
T
=V
inf
+V
U
+V
B (1)
The three potential paths for stormwater runoff have the following pollutant removal efficiencies: (1) enter the BMP and completely infiltrate into the ground beneath the surface providing 100% pollutant reduction; (2) enter the BMP, partially infiltrate into the ground providing 100% pollutant reduction for this portion of rainfall infiltrated, and partially discharge the remaining through an underdrain where it is conveyed to surface waters providing a BMP-specific fraction (e.g. 35-65%) pollutant reduction for this portion depending upon the volume of water that fully infiltrates versus the volume entering the underdrain system; or (3) bypass the BMP providing 0% pollutant reduction for this portion. The process is iterative, and the BMP is sized such that VB goes to zero to avoid having any runoff by-pass the BMP.
Many BMPs have been designed and constructed across the United States using conservative values for the infiltration rates recommended by existing design guidance documents. Given the conservative nature of these standards, when a BMP has an underdrain system 14, it is likely that many BMPs are infiltrating larger fractions of stormwater volume passing through them than they are currently being credited. However, prior to the present invention 10, it is not known in the art how to determine how much infiltration is taking place in order to have data to support a larger credit for removal of TSS and TP than provided in the initial design.
In use, the BMP system 10 of the present invention can be implemented into new or existing BMP systems with underdrains 14 to show the actual reduction in total suspended solids (TSS) and total phosphorus (TP) so that municipalities can demonstrate that the BMPs actually remove more TSS and TP than estimated in current passive design according to the current conservative design guides when demonstrating or evaluating compliance with the EPA runoff requirements. As part of the compliance strategy, the present BMP system 10 can also be linked with a private BMP's implementing system 10 through which a municipality may contract or otherwise consider in its compliance efforts and have the actual data to back up the private BMP's contribution to such compliance. This has the potential to save municipalities, and ultimately taxpayers, a substantial amount of money in both reduction of CAP-X and ongoing operations and maintenance while still providing the necessary runoff and environmental standards set forth by a state or the EPA.
In one embodiment of BMP system 10 of the present invention operating with an underdrain 14, the fluid level of the BMP system 10 may be monitored using one or more fluid level sensor(s) 24. In one embodiment, the fluid level sensor 24 may be a mechanical float sensor. Other types of fluid level sensors can also be used. The float of the fluid level sensor 24 has a specific gravity less than 1.0. When installed within a BMP system 10, the float rises as water enters the system 10 and is present in storage gallery 54, sending a voltage reading to a wired computer 36. The voltage is received by the computer 36 and then sent wirelessly using cellular, Wi-Fi, or LoRa antenna 42 to a cloud-based database 48. Data transmission to the cloud can also be accomplished via hard-wired connections to existing site infrastructure where available. Once in the cloud 48, voltage is interpreted and converted by software to a corresponding water level. Voltage may also be interpreted via edge computing at computer 36. In one embodiment, the water level can be measured to around a 0.25″ resolution, but depending upon the application and/or the water level sensor 24 being used, higher or lower sensitivity may be implemented. The overall measuring range for the fluid level sensors 24 used in the present BMP system 10 can vary from as low as a couple of inches to higher than fifty feet.
At least one real-time-control (RTC) valve 16 is installed at the BMP outlet 50 (i.e. the end that drains to storm sewer or open water). In the present system 10, the valve 16 is maintained in a normally closed condition. This means that, under normal conditions, any water entering a BMP system 10 (and its underdrain 14) is not allowed to exit the system 10, except through infiltration into subgrade 28 or through evaporation. If subgrade infiltration and/or evaporation is not capable of draining a BMP 10 within specified drawdown times, the valve 16 can be remotely opened. The valve 16 can also be remotely opened if there is risk of system 10 overflow or bypass. In other words, if significant precipitation events occur or normal precipitation events spaced closely together (i.e. back-to-back storms), there is potential for the BMP system 10 to overflow if infiltration through subgrade 28 is the only exodus path for the filtered runoff. The valve 16 should be opened in this scenario to ensure all runoff enters the BMP system, even though most of the runoff would be draining through underdrain 14 discharge instead of infiltration. It is better for runoff to exit the underdrain 14 after being filtered through a BMP system 10 than bypassing a BMP altogether and not having any removal of TSS or TP.
In one embodiment, valve 16 could be a variable flow valve so that the outflow rate could be optimized based upon the measured precipitation from the rain gauge 32 so as to optimize subgrade infiltration, but still meet required drawdown times. Further, the operation of valve 16 could be used to manage the outflow rate with other types of BMPs for at least the following purposes: maximize the time water is stored to maximize settlement of pollutants, maximize the use of storage capacity to even out or manage the load of stormwater runoff being introduced into the downstream network and/or processed in water treatment plants, or other optimization of system capacity limits or environmental compliance issues.
The valve 16 can be opened or closed remotely using online dashboard controls, which connects the BMP system 10 with a remote computer through the internet. Notifications via email or text messages can be sent to asset owners/managers alerting them of high-water levels. High water level thresholds may be defined by the asset owners/managers. Remotely opening the valve 16 can be done manually through the online dashboarding environment or physically in the field, or it can be done autonomously by the system using BMP water level and local rainfall data. For example, if water level rises above a user-defined threshold, is still in the drawdown period from the previous rain event, and it begins to rain again, the system 10 could automatically open the valve 16 to drain the system 10 and provide storage capacity for the new runoff.
In another embodiment, one or more overflow standpipes 22 can be installed immediately upstream of the RTC valve 16. The overflow standpipe 22 would minimize the potential for any stormwater runoff to bypass the system 10. In this scenario, the RTC valve 16 would only be opened if the system 10 did not drain within the specified drawdown time, not to generate storage capacity ahead of another rain event.
One embodiment of BMP system 10 measures and documents at least the following for stormwater BMPs either in temporal proximity to a precipitation event or in real-time: site-specific rainfall, temperature, barometric pressure, and relative humidity using a weather sensor 30; current water level within BMP system 10 using a fluid level sensor 24; volume of stormwater infiltrated into subgrade 28 using a computer 36 and/or fluid level sensor 24 and/or the measured rainfall amounts from rain gauge 32 using known computational methods; volume of stormwater discharged through underdrain 14 or other outlet pipe measured or calculated using a flow sensor and/or the flow properties of the outflow valve 16; and pollutant removal efficiency using the volume of stormwater infiltrated into subgrade 28, the volume of water discharged through the one or more outlet 50 of underdrain 14 or other outlet pipe.
As an example of why the present BMP system 10 should be implemented into a compliance program, there have been instances in a Southeast WI municipality where permeable pavement underdrain monitoring after rain events showed little to no flow through the underdrain. This indicates that for at least some BMPs, most, if not all, stormwater runoff is actually infiltrating into the subgrade 28 rather than being discharged through the underdrain.
In contrast, when comparing this real-world observation to the WinSLAMM software model used to size the permeable pavement BMP and to quantify its pollutant removal efficiency, the model uses a conservative subgrade seepage rate of only 0.04 in/hr. This value is about as low as possible and is representative of a silty clay subgrade material. If the subgrade 28 material can only infiltrate stormwater at a rate of 0.04 in/hr as indicated in the model, the underdrain 14 monitoring efforts would have revealed higher flows after rain events. Given the discrepancy between the model and what is being seen in the field, it is likely the BMP at hand can receive more pollutant removal credit than is currently being utilized for the compliance analysis. This would benefit the property owners as well as the municipalities (and the environment) as the actual pollutants being discharged is less than what the model has estimated.
Measuring the actual pollutant removal efficiency using BMP system 10 is important because communities which drain to impaired bodies of water, as identified by states and approved by the Environmental Protection Agency (EPA), are required to meet a pollutant budget commonly referred to as a Total Maximum Daily Load (TMDL). TMDLs have been established for watershed basins draining to impaired waterways across the United States. Each basin's TMDL is unique and can be further discretized into separate reachsheds. Pollutant load allocations are defined for each reachshed and depend on the type of impairment present within the waterway to which the reachshed drains.
As an example, parts of the storm sewer system and waterways in the Village of Whitefish Bay (WFB) in Wisconsin drains into the Milwaukee River. WFB is a relatively small municipality located in SE WI, just north of Milwaukee. The Milwaukee River Basin is broken up into many (30+) reachsheds, each with their own pollutant load allocations. The portions of WFB that drain to the Milwaukee River occupy reachsheds MI-27 and MI-32. These reachsheds in portions of WFB are subject to the TMDL requirements. The portions of WFB not included in these reachsheds drain directly to Lake Michigan and are not subject to TMDL requirements; rather, they must conform to WFB's Municipal Separate Storm Sewer (MS4) Wisconsin Pollutant Discharge Elimination System (WPDES) permit requirements. See 2017 Village of Whitefish Bay TMDL Stormwater Quality Management Plan—Report, prepared by Strand & Associates.
The pollutant load allocations per TMDL reach of MI-27 and MI-32 are as follows (expressed as % reduction from baseline conditions):
For this application, we will focus on how the information related to the removal of TSS and TP from the run-off for MI-27 may be shown using the presently described display system. What these numbers mean is that WFB must remove 73% of the TSS and 54% of the TP from their runoff in reachshed MI-27 to achieve TMDL compliance. To comply, WFB must determine how much TSS and TP they are currently removing. If WFB can determine what their current stormwater BMPs are capable of in terms of pollutant reduction for TSS and TP, they can determine their compliance gap (i.e. the delta between where they are currently and where they need to be for EPA compliance).
One method for using BMP system 10 is shown in
In step 1004, the reductions provided by the BMPs are determined by accounting for existing stormwater BMPs and their ability to capture pollutants. Typically, and conventionally, this is a task completed by engineering consultants who rely heavily on governmental guidance documents and SLAMM models to come up with the pollutant reduction credit. These calculations are currently being performed using the conservative industry design guidelines and methods. After an analysis is performed, in step 1004, the results can be expressed in the form of total pounds of pollutant removed or expressed as a percent reduction in pollutant for the reachshed. As long as the BMP is designed, constructed, operated, and maintained in accordance with the guiding technical standards, pollutant reduction credit commensurate with the BMP's pollutant removal ability is given to the community.
At this point, in step 1006, the community can estimate their compliance gap, if any. Pollutants captured by existing BMPs, expressed as percent reduction within the reachshed, are compared to the TMDL goal for that reachshed. In the WFB example (specifically reachshed MI-27), there are four existing structural BMPs reducing TSS by 14.2% and TP by 10.5%. This means there are reduction gaps of 58.8% and 43.5% for TSS and TP, respectively using the current conservative industry design guidelines and methods—see 2017 Village of Whitefish Bay TMDL Stormwater Quality Management Plan—Report, prepared by Strand & Associates.
In step 1008, the community will need to determine how to make up for the gap, either by building additional BMPs or by purchasing compliance credits. In step 1010, the community will need to document all of the compliance efforts to demonstrate compliance with the TMDL for both the State and the EPA.
TMDL communities, like WFB, can benefit from the present BMP system 10 by using the actual measurements to demonstrate that the existing infrastructure is more efficient than SLAMM models and current conservative industry design guidelines and methods are giving them credit.
For a more specific example,
In this example, City X 600 knows they are not in compliance with the EPA requirement 514 for water quality of run-off water. Based on their consultant's reporting, City X 600 has already constructed three BMPs (502, 504, 506 in
As shown in
Now, using the BMP system 10 of the present invention, as an alternative step 1004, City X 600 can install BMP system 10 into BMPs 502, 504, and 506, all of which are already-built BMPs owned and maintained by City X 600. In this example, after installing and monitoring BMP system 10, it is measured that BMPs 502, 504, and 506 each show a 25% increase in pollutant-removing efficiency as shown in
Let's now assume City X 600 focuses on Alternative 2 and decides to install the current invention into the privately-owned BMP 500. Since all BMPs 502, 504, 506, and private BMP 500 are assumed the same in this example, City X 600 would again see a 25% increase in pollutant-removing efficiency. In total, with four BMPs 500, 502, 504, 506 retrofitted with the BMP system 10, the demonstration of the actual performance of these BMP systems increases the removal performance of the four existing BMPs to be the equivalent of adding one whole BMP. This would bring their tally up to five total BMPs in actuality, compared to four under the conservative modeling method. At five equivalent BMPs provided by BMPs 500, 502, 504, 506 including the present BMP system 10, City X 600 has achieved compliance with an alternative that reduced their CAP-X costs by 100% because it does not require the construction of any additional BMPs 508 or 510. In some cases, because of the conservatism in the existing design methods and the variations in the actual performance of a BMP, it is also likely that some BMPs prove to provide more than 25% increased efficiency. In this situation, City X 600 would have excess pollutant removal capacity and therefore may be able to turn their existing stormwater BMPs into revenue generating assets for their stormwater utility funds by selling credits to other communities in their basin.
Moreover, in some embodiments, the present BMP system 10 can be actively managed in operation to maximize the pollutant-removing efficiency of a system based upon the experienced weather and environmental conditions to provide even better environmental benefit. For example, underdrain 14 of BMP system 10 may be closed during certain rain events to maximize infiltration through the soil and subgrade 28, and BMP system 10 may open the control valve 16 once a pre-determined rainfall amount or rate is obtained so as to maximize the amount of time that the BMP operates at 100% pollutant-removing efficiency through infiltration only.
By retrofitting existing BMPs with the present BMP system 10, TMDL communities have an ability to significantly reduce their stormwater infrastructure CAP-X costs while still obtaining compliance, and in some cases, generate excess income through selling credits to other communities if actual performance of the BMPs exceeds TMDL requirements for each TMDL reach subject to environmental regulation.
Tables 1-4 and
While this patent describes display system 400 for displaying EPA TMDL compliance progress, it should be noted that the system 400 is equally applicable to Municipal Separate Storm Sewer (MS4) permitting compliance where actual conditions can be monitored and compared to established models which are used in permitting and ongoing compliance programs. Further, this system can be extended to volume monitoring activities and applications included within combined sewer systems and networks.
Tables 1 and 3 provide baseline pollutant loads for Total Suspended Solids (TSS) and Total Phosphorus (TP), broken down by reach and subreach according to established regulatory models. Progress toward TMDL compliance is shown for each reach in both pounds and percent based upon modeled information in Table 1. Table 3 provides updated progress toward TMDL compliance after incorporating the present system 10 and utilizing the system to observe and measure performance data of each existing BMP 612, 616, 618, 622, and 624, new BMP 626, and private BMP 628.
Table 2 compares modeled pollutant reductions with TMDL required reductions to quantify compliance gaps and corresponding TSS and TP cost gaps.
Table 4 compares updated, measured pollutant reductions with TMDL required reductions to quantify compliance gaps (or credits) and corresponding TSS and TP cost gaps (or credits).
The numbers and call-outs shown in
When looking at the sunburst plots provided in
As shown in
As shown in
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting.
The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention.
As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.
35%
64%
19%
20%
45%
This application claims the benefit of U.S. Provisional Patent Application No. 62/704,130, filed Apr. 22, 2020, the entire disclosure of which is hereby incorporated by reference, and also claims the benefit of U.S. Provisional Patent Application No. 62/704,759, filed May 27, 2020, the entire disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62704130 | Apr 2020 | US | |
| 62704759 | May 2020 | US |
