Abstract:
An apparatus for controlling the fluid flow rate from a drainage pond that is common in developed sites where the drainage pond is adapted to supply a degree of fluid capacitance so the runoff does not overflow downstream creek beds and the like. The method and apparatus for controlling the fluid draining from a pond comprises a system for allowing a higher flow that is allowed by regulatory bodies when the pond is at a lower level so the pond drains more quickly when it is at a lower water level. Thus the apparatus allows for a smaller retention pond.

Description:
RELATED APPLICATIONS 
   This application claims priority benefit of U.S. Ser. No. 60/552,981, filed Mar. 12, 2004. 

   BACKGROUND OF THE INVENTION 
   The disclosure relates to a hydrostatic pressure flow control device particularly adapted for an above ground or below ground holding pond (generally referred to as a pond) that is adapted to collect storm water where the flow control device is in fluid communication therewith. The general purpose of the pond is to prevent a large influx of water into a nearby stream or the like which can potentially cause environmental damage. Many regulations require storm water and other runoff water to be directed into a holding pond and then discharged at an adequate flow rate to meet regulated criteria. 
   In an urban development where forest is removed and is replaced with items such as concrete and the like which have distinctly different runoff characteristics, a detention pond must be implemented for handling storm water. In general, there are two things which must occur with storm water: it must be cleaned, and it must be metered. In one preferred form, there is bioswale that is positioned between a control structure and a main pond volume. In low flows, the bioswale acts as a filtering device, whereby water passes therethrough due to gravitational flow to the control structure. In high flows, the control tower essentially backs up the flow, thereby filling the bioswale and the main large tank. In the control structure there is generally an orifice in the upper portion that is adapted to have the water pass therethrough in a “design H” situation which is essentially a two-year flood, whereby the maximum amount of allotted throughput of water, by the local environmental standards, passes therethrough. Of course, this does not occur until the water level is quite high, and the entire pond is filled up to the upper portions and the maximum capacity thereof. 
   Generally, state and Federal Departments of Ecology are concerned with fluid throughput between various creek beds and the like, so ecological systems such as salmon eggs are not washed out during a deluge or any form of rain or flood. Essentially, the detention pond is adapted to mimic the pre-developed condition, whereby the dampening effect by the inherent capacitance of all of the forest and under brush. Development such as rooftops, parking lots and other hard surfaces decrease an area&#39;s water capacitance. Therefore, the natural flow control is effectively reproduced by the pond and a flow metering device. 
   It should be noted that there are three essential flow durations (rates over a set period of time) that are allowed: 50% of the two-year flood, 100% of the ten-year flood, and 100% of the hundred-year flood throughputs. These amounts are flow durations, which are measured in cubic feet per second multiplied by number of hours. 
   Therefore, it is advantageous to have a maximum allowable throughput during the various height conditions of the pond. In one form, this is accomplished by having a fixed hydrostatic head with a known orifice where the head will stay constant regardless of the water level as shown in the detailed description below. In one form, this head is 49% of a two-year amount, which is the maximum allotted throughput amount as per the Department of Ecology standards (at the present time of filing in the Inventor&#39;s state of residence which is Washington State). 
   Therefore, it is extremely advantageous to have a controlled higher throughput of fluid so that the backup of water in the settling pond is a lesser net volume. This allows for a greater amount of real estate to be utilized for other, more usable land or preserved land in the pre-developed state. 
   The apparatus as described further below functions as an early release mechanism. In the northwest region of the United States, a thirteen-acre developed site would normally require a 41,400 square foot sized pond with prior-art flow control systems in place. With the invention as described below in place, the pond is essentially reduced in topographical square feet by 38%. It should be noted that given the angle of repose of the soil, there is a fixed amount of depth and volume that can occur given a certain square-footage of allotted space for a pond. Additionally, in some embodiments the items are submerged in a concrete box beneath usable soil; however, this is an expensive installation, and of course, reducing the overall size is potentially advantageous. 
   With regard to the above example that was in use, the implementation of the invention would save approximately $75,000 in estimated costs using the flow control system as claimed. 
   In the Civil Engineering pond design and installation disciplines, there is psychological trend to guard against the maximum flow and not be concerned with the flow rates that occur immediately leading up thereto. In other words, the prior art is concerned with the maximum flow rates where the damage can occur and not exceeding these flow rates; however, this line of thinking has a tendency to neglect the flow rates immediately preceding and leading up the maximum allowable flow rate. A system as described below provides a maximum allowable flow rate as soon as possible to increase the net volume passing through the pond and the system hence allowing a smaller volume pond to be in place. 
   SUMMARY OF DISCLOSURE 
   In one form there is provides a flow control module having an entrance passage that is adapted to communicate with a fluid, where the fluid is in communication with a drainage pond. An orifice is provided at a position in communication with the entrance passage, where the orifice size and height of the water acting thereon provides a hydrostatic pressure acting upon the orifice allows a prescribed fluid flow rate to flow therethrough at a substantially similar rate at a first water level height and second water level height of the drainage pond. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a partial cross-sectional view of an embodiment of a flow control system; 
       FIG. 2  shows a partial cross-sectional view of a flow control system where the water level is at a lower position in the container; 
       FIG. 3  is a cross-sectional view of the flow control orifice taken at line  3 — 3  of  FIG. 1 ; 
       FIG. 4  shows another embodiment of the flow control system; 
       FIG. 5  is a cross-sectional view of the flow control orifice taken at line  5 — 5  of  FIG. 4 ; 
       FIG. 6  is another embodiment of a flow control system; 
       FIG. 7  is another embodiment of the flow control system whereby a cross-sectional area of a passageway varies with respects to hydro-static pressure; 
       FIG. 8  is a schematic view showing and example of a doughnut cross-sectional area provided to control the water flow. 
       FIG. 9  shows a partial cross-sectional view of a flow control assembly comprising the control container and the flow control system contained therein where the water level is at a low flow state; 
       FIG. 10  is a partial cross-sectional view similar to that in  FIG. 9  where the water level is at a higher position within the control container; 
       FIG. 11  is a cross-sectional view of the flow control module that is adapted to be fitted to a water receiving component; 
       FIG. 12  is a cross-sectional view taken at line  12 — 12  of  FIG. 9  showing the flow control system as well as the fluid receptacle and first and second fluid passages adapted to receive fluid in very heavy downpours. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In general, the flow control assembly  20  comprises a control container  28  and a flow control system  21 . The flow control system  21  comprises a flow control module  22  and a water receiving assembly  24 . The general environment of the flow control system  20  is within a drainage/reservoir pond that has some form of a container  28  adjacent thereto which houses a body of water indicated at  30 . The body of water  30  comprises an upper surface portion  31 . Of course hydrostatic pressure results at any depth below the upper surface  31 . There also is a storm drainage or the like (not shown) that is in communication with the water receiving assembly  24  that is adapted to receive the fluid therefrom. Further, there is a pond where the outlet control structure/container  20  is in communication with the pond which could be quite large up to 3 acre-feet. The volume of the control container is approximately a 48″ circle and about 8–16 feet deep which is about several hundred cubic feet. The container  28  also provides a barrier from the pond. In general the flow control assembly  20  allows for an expedient draining of the pond and the submerged water intake (discussed further herein). The control container  28  allows for a natural filter to screen out debris and other floating material or liquids. 
   The flow control assembly  20  comprises a flow control system  21  and the control container  28 . The flow control system  21  in one form comprises a fluid control module  22  that in general is adapted to in one form maintain a substantially static head pressure with respect to an orifice described further herein. The flow control module  22  comprises an intake portion  40  in communication with a surface defining an interior chamber region  41  and a discharge portion  42  as shown in  FIG. 3 , the discharge portion has a flow control orifice  44  that has a diameter  46 . The diameter  46  corresponds to a cross-sectional area allowing fluid to flow therethrough. In one form this is a circular cross-sectional area; however, other cross-sectional areas can function as well. In one form, the intake portion  40  comprises a filter  50  as shown in  FIG. 1  that is adapted to prevent entry of larger debris which can be problematic for clogging the flow control orifice  44  or altering the flow of the water passing therethrough or altering the diameter in various sections of the discharge portion  42 . 
   As shown in  FIGS. 1 and 2 , from the centerline of the flow control orifice  44  to the top of the surface of the body of water  31  is defined as distance  52 . It should be noted that the combination of the set distance  52  and the size of the flow control orifice  44  is such to provide a “maximum allowed flow rate”. In general the maximum allowed flow rate is just below the 50% of the two-year flood, in one form 45%–49% of this value or a target goal of 48% of this maximum allowable throughput to proved a certain degree of error in the system to be below the statutory upper limit of 50%. It should be reiterated that in general there are three essential flow rates that are allowed: 50% of the two-year flood, 100% of the ten-year flood, and 100% of the hundred-year flood throughputs. In one form the embodiment would allow flow rates that are with about 5% of the maximum allowed by the controlling authoritative body (e.g. Department of Ecology), and in other forms with in 2% of such maximum allowed flow rates. However, maximum allowed flow rate is defined as any desired flow rate in the jurisdiction where the flow control structure operates. 
   Referring now to  FIG. 1 , the flow control module  22  further comprises a buoyancy system  60 . In general, the operational aspects of the buoyancy system  60  is to maintain the vertical position of the flow control orifice  44  with respect to the upper surface of the water  31 . In one form, as shown in  FIG. 1 , the buoyancy system comprises a buoyant member  62  and a frame section  64 . The frame section  64  as shown in  FIGS. 1 and 3  provides a surface having an opening  66  that is adapted to securely mount the discharge portion  42  thereto. 
   The water receiving component  24  comprises a vertical displacement system  70 . In one form, the vertical displacement system comprises a rigid vertical or substantially vertical tube  72  which can be made of a metallic or PVC pipe. 
   The vertical tube  72  has a central cavity region  69  and a surface defining a passageway  73  that is in communication with the discharge portion  42  of the flow control module (see  FIG. 3  for cross sectional view). It should be noted that the flow control orifice  44  need not be positioned directly at the discharge portion  42 , but rather and may be in a more preferable form, be positioned anywhere along the tubing sections of the flow control module  22  such as near the screen  50 . The important aspect of the flow control module  22  is to provide a substantially constant flow rate in normal conditions whereby the outlet orifice is at  80  certain distance  52  from the water surface  31  and this distance is maintained irrespective of the heights of the water level  31  with respect to the container  28 . In the embodiment shown in  FIGS. 1–3 , the tube  70  has an extension  75  that is adapted to receive the slot region  77  of the frame section  64 . This allows for minimal rotation of the frame section  64  which is adapted to position the discharge portion  42  to be aligned and in proper communication with the passageway  73 . A further embodiment discussed below alters the orifice size with respect to the heights to control the water fluid rate. 
   As shown in  FIGS. 1–3  the flow control system  24  as previously mentioned comprises the vertical displacement system  70 . As shown in  FIGS. 1–2  a bellow  80  is provided which allows an accordion like extension and contraction to provide vertical displacement of the flow control module  22 . The bellow comprises an upper end  82  and a lower and  84 . In one form, the bellow is set at a preset length where the maximum extension of the bellow  80  will only allow the flow control module  22  to extend to a maximum vertical position. The flow control module  22  is attached to the upper end  82  of the bellow  80 . As shown in  FIG. 1 , the flow control module  22  is located at the upper portion of the tube  72 . In one form, the flow control module has a maximum upper location which could be similar to the location as shown in  FIG. 1  whereby if the water level were to continue to rise, the flow control module will not rise in proportion to the increase of the water level  31  but be held in place by the bellow  80 . Thereafter as the water level rises, the water will be exposed to fluid passages  86  and  88 . The fluid passages  86  and  88  are one form of a higher flow maintenance system  85 . The operation of the higher flow maintenance system  85  is too allow for additional fluid to pass to the drainage (not shown) in more extreme rainfall and water runoff situations which can occur at various times of the year or at peak times in increments of years or decades (and in some cases centuries for a 200 year flood). In general, when the rainfall or water runoff is very excessive, many regulations allow for emergency flows to be in effect whereby the flow rate exiting the water receiving component  24  can be higher than the normal regulated amount. 
   Therefore, the fluid passages  86  and  88  provide for additional fluid passageways to increase the gross flow rate. Further, because the flow control module  22  is fixed in the vertical direction, the hydrostatic pressure will increase whereby increasing the flow through the flow control orifice  44 . Of course any number of fluid passages  86  and  88  can be provided. Alternately, a slot like system which one form is triangular in shape with the pointy portion located at the lower regions can be employed. Further, the upper portion  73  of the tube  72  can be opened or set to a certain diameter to allow additional fluid flow when the water level  31  is extremely high. In some cases where the “200 year flood” occurs a massive amount of throughput is allowed where an extremely heavy rainfall or water runoff is present. 
   Now referring to  FIG. 2 , it can be seen that the water level  31  is at a first water level height much lower position then with respect to the second water level height as shown in  FIG. 1 . This water level within the control structure  28  represents the water level in the adjacent pond. Because the pond has a much larger area, the volume within the pond is considerably lower in  FIG. 2  than that as shown in  FIG. 1 . However, it is apparent that the relative positioning of the water level  31  with the centerline of the discharge portion  42  is substantially the same as that of  FIG. 1  if not exactly the same. Of course various minor waves and other such effects will create slight deviations in the hydrostatic pressure that is experienced at the discharge portion  42 ; however, it can be appreciated that the hydrostatic pressure at the discharge portion  42  is substantially constant irrespective of the water level within the control container  28  and the pond in fluid communication with the control container  28 . 
   Therefore, it can be appreciated that the flow control module  22  in combination with the water receiving component  24  essentially operates as a displaceable unit in the vertical direction (of course with or without the option of lateral displacement which does not affect the operations) whereby in one form a buoyancy system  60  provides the altitude control with respect to the water surface  31 . 
   Now referring to  FIG. 2 , the flow control system  20  is shown in normal operation. A normal condition is defined where the height of the flow control module  22  is substantially constant with respect to the water level  31 . A higher flow condition is defined as discussed above in reference to  FIG. 1  where the water level  31  will rise above the set distance indicated at  52  and possibly begin to engage the fluid passages  86  and  88  of the higher flow maintenance system  85 . An extreme flow condition is defined where the water level is at a maximum value and a high fluid throughput system such as the opening  73  is employed that allows for a high volumetric fluid flow rate to pass therethrough when the runoff or rainfall or other form of acquiring water is at an extremely high intake rate. 
   Most of the time the flow control system  20  is operating in the normal flow condition in a manner as shown in  FIG. 2 . When the water level  31  is at a moderate level, instead of having a lower hydrostatic pressure acting upon an orifice, it can be appreciated that the same hydrostatic pressure as shown in  FIG. 1  is the same as the hydrostatic pressure dictating the flow rate as shown in  FIG. 2 . In other words, the distance  52  is substantially similar. A situation as shown in  FIG. 2  occurs where a reasonable rainfall or spring runoff occurs and the container  28  has received a certain influx of fluid. Because the flow control system  22  can pass fluid therethrough at the maximum allowed rate at a lower fluid level and a higher fluid level as shown in  FIG. 1 , the net volume of the pond can be designed smaller (approximately 10–40 percent smaller) than with a system that does not allow for a constant maximum throughput of water. Further, the flow control assembly  20  helps to drain ponds more quickly which prevents the potential hazard that any body of water presents such as a liability to children or a nesting area for ducks near an airport. 
   Therefore in operation, as shown in  FIG. 2  the water level  31  will continue to drop at a normal maximum rate which is defined as the rate of flow that is allowed or desired depending upon the other circumstances of where the water receiving component is connected (e.g. the connected sewer system may have a desirable influx of fluid rate that is lower than the regulated amount). Therefore, the water level in  FIG. 2  will continue to drop at a steady rate until the bellow  80  is sufficiently compressed and the water level essentially runs at or slightly below the intake portion  40   
   It should be noted that the water receiving component  24  in general has a large inner diameter  90  which correlates to a large cross-sectional area so the water essentially drops when injected to the central cavity region  79  whereby a negative gauge pressure is not created at the discharge portion  42 . In other words, the potential energy of the falling water indicated at arrow  92  in  FIG. 1  disperses its energy by impacting the lower region of the tube  72  and no suction is incurred whereby lowering the pressure near the discharge portion  42  which would induce a greater fluid throughput therethrough. Further, the upper portion of the tube  70  is vented to atmospheric which further reduces any possibility of creating a relatively lower pressure at the discharge portion  42  than atmospheric pressure. It should be noted that the vertical tube  72  need not be cylindrical but could function as a variety of cross-sectional shapes other than the cross-sectional cylinder as shown in  FIG. 3 . Therefore, the diameter  90  is really a representation of the relative dimensions of the cross-sectional area between the water receiving component  24  in the flow control orifice  44 . As mentioned above, in one form the cross-sectional area of the water receiving component  24  is larger than that of the flow control orifice  44  which is designed to control the flow rate through the control module  22 . However, by having a portion of the tube  70  exposed to atmospheric, the cross-sectional open area of the tube  70  need not be as large because the discharge portion  42  is essentially venting to atmospheric pressure. 
   There will now be a discussion of another embodiment with reference to  FIGS. 4–5 . Similar components will be designated with several numerals except with the alphanumeric character “a” positioned at the end of the numeric reference. As shown in  FIG. 4 , the flow control module  22   a  comprises a buoyant member  62   a . The buoyant member  62   a  has a surface defining an opening  63  that allows ventilation to an interior chamber region  65 . The flow control module  22   a  as shown in  FIG. 4  has a discharge region  42   a  which comprises an flow control orifice  44   a  which is positioned at a strategic location with respect to the water surface level  31  to provide a consistent head pressure. The water receiving component  24   a  comprises a vertical displacement system  70   a  which in one form is a flexible tube that is connected to a drainage line  95 . In general, the cross-sectional area of the vertical displacement system  70   a  is sufficiently larger than the flow control orifice  44   a  so negligible headloss is incurred other than the headloss through the flow control orifice  44   a . As shown in  FIG. 5 , the flow control orifice  44   a  is shown where the diameter  46   a  is calculated in conjunction with the distance from the flow control orifice  44   a  to the height of the water level  31  to produce a normal flow rate described above. 
   As shown in  FIG. 4  the underflow of the water into the central chamber  41   a  is represented by arrow  65  and prevents the introduction of floating debris or low density fluids such as oil or other hydrocarbon based substances. 
   It should be noted that the vertical displacement system  70   a  as shown in  FIG. 4  is particularly advantageous in new construction where the lower region indicated at  81  is allowed to sink deeper into the tank region  28   a  whereby allowing for the flow control module  22   a  to drop vertically downwardly (and optionally in the horizontal plane if necessary which does not affect the flow operations of the flow control module  22   a ). 
   When the flow control orifice is positioned at the area indicated that  42   a , the distance to this orifice from the surface  31  is defined as the distance  52   a.    
   As further seen in  FIG. 4 , a higher flow maintenance system  85   a  is provided where a plurality of fluid passages  86   a  are strategically positioned to account for higher flow conditions. In an extreme flow condition an upper orifice indicated at  73   a  is provided that allows for a greater throughput of fluid along the tube  91 . The higher flow maintenance system  85   a  essentially allows for another fluid passage to directly communicate with the outlet passageway  95 . 
     FIG. 6  shows another embodiment which is a quasi combination of the previous two embodiments in general, the flow control module  22   c  (add to figure) is similar to the flow control module  22   a  of  FIG. 4  where a flexible connection tube  110  is provided. In general, the buoyant member  62   c  and the buoyant member  62   d  operate in parallel whereby the previously described outlet orifice can either be positioned with respect to either float  62   c  or  62   d . In other words, in general the flow control orifice  44  which has a inner diameter that essentially controls the flow rate can either be positioned at a fixed location with respect to the float  62   d  as indicated by  44   c  or the positioned at the position indicated by  44   c ′. If the flow control orifice is positioned at the location indicated at  44   c ′ then in essence, the vertical position of this orifice with respect to the float  62   c  dictates the flow rate where the fluid can freely flow with minimum head through the flexible tube  110 . Alternatively, because the floats  62   c  and  62   d  are both positioned at the water level and the outlet portion  42   c  is at atmospheric pressure and at a fixed distance from the water level  31 , the flexible tube  110  having an inner cross-sectional area can function as a flow control module where the length of the tube and the inner diameter functions to provide a proper headloss for the designed flow rate to pass therethrough. 
   Depending upon where the flow control orifice is positioned, the height can be calibrated therefrom for a desired flow rate. For example, if the flow control orifice is positioned at the location indicated at  44   c  than the height or distance  52   b  is used to calculate the water flow rate therethrough. If the flow control orifice is positioned at the location indicated that  44   c ′ then the height indicated at  52   c  is employed for the water flow calculations. It should be noted that the height of the distance between the flow control orifices and the water level is generally about 6 to 12 inches and in one form about 8 inches. Generally the orifice is submerged at least 3 inches for a relatively static head pressure. Of course in the broader scope a wide range of heights can be employed. In some forms where the buoyant members of the various embodiments will fluctuate in height with respects to the water level, it may be advantageous to have a higher water column it from the flow control orifice to the water level where the tolerances for the diameter or open area of the flow control orifice is held very tightly. In other words, where the fluctuation in water height may vary as the buoyant member soaks up with water over time, the other component, the size of the orifice, is measured precisely. In the alternative, if the water level is held to a very tight tolerance with respects to the orifice for all-time no matter what the conditions, the height from the water level to the orifice can be lowered if there are poor tolerances for the size of the orifice. 
     FIG. 7  shows a schematic view of a flow control system  122  where a fluid receiving portion  124  which is connected to a storm sewage drain or the like at an interface portion  126 . The interface portion  126  has a cross-sectional diameter which in one form or the cross-section is tubular, the cross-section is defined by a diameter  128 . A flow control valve  130  is provided which comprises a flow control member  132  and a control portion  134 . The flow control member  132  comprises a conical or frusto-conical outer surface  136  or any other tapered surface that increases in cross-sectional area with respect to the direction indicated by arrow  138 . The control portion  134  has a head receiving member  140  and a biasing member  142 . The housing region  144  comprises an inner chamber  146  that is adapted to be at a fixed number of moles of molecules. As the head pressure increases and results in a force upon the head receiving member  140  (where the cross-sectional area of the head receiving member  140  multiplied by the mean pressure acting thereon creates said force) the flow control member  132  is biased toward the interface portion  126  against the force of the biasing member  142 . It should be noted that the smallest net cross-sectional area is strategically positioned at the portion where the conical or frusto-conical surface  136  is near the interface portion  126 . In other words, as shown in  FIG. 8 , the central donut shaped region  150  is calculated to dictate the amount of water flow therethrough. As the head pressure increases, the flow control member  32  is inserted deeper into the interface portion  126  whereby decreasing the donut shaped area  150  and substantially maintaining the flow rate. In other words the head pressure goes up and the exposed surface area for water passage goes down. The rate of frusto-conical change of the surface  136  and the spring constant of the biasing member  142  as well as the exposed surface area of the head receiving member  140  are adjusted to allow the proper flow rates in various conditions to remain substantially constant at higher water levels. It should be noted that the surface  136  of the flow control member  132  need not be a linear increase in the conical dimension but could take a variety of forms such as a bullet nose tapered increase whereby as the flow control member is inserted into the interface region  126 , the rate of change of the open area  150  as shown in  FIG. 8  would decrease whereby allowing greater flow to pass therethrough as the water level reaches the higher levels in the container (not shown in  FIGS. 7–8 ). The apparatus  122  would essentially be positioned at the lower portion of a tank similar to that of tank  28  in  FIG. 1  and be calibrated for various water levels. It should be further noted that although  FIG. 8  shows circular surfaces, any variety of cross-sectional type surfaces can be employed. The important aspect is to have a changing cross-sectional area  150  with respect to the hydrostatic head pressure which is a function of the water level. Of course maximum flow control elements such as that as shown in  FIG. 4  above where a vertically extending tube connected to the water receiving component  24  can be employed to increase the flow throughput in higher flow conditions and extreme flow conditions as defined above. 
   Now referring to  FIGS. 9–12 , there is shown a most-preferred embodiment. In general, the control container  28   e  is constructed in a similar manner as the control container shown in previous figures. As further shown in  FIG. 9  there is a flow receptacle  33   e . In one form, the flow receptacle  33   e  already exists within the control container  28   e  and the flow control system  21   e  is retrofitted to an existing or already fabricated control unit  28   e  and flow receptacle  33   e . The flow receptacle  33   e  further comprises a high flow maintenance system  85   e  having a first fluid passage  86   e  and a second fluid passage  88   e . The fluid passages  86   e  and  88   e  operate in the same manner as previously described above with reference to  FIG. 1 . The flow receptacle  33   e  further comprises a discharge/drainage line  95  that is in communication with a downstream drainage system such as that which is commonly provided when designing the entire drainage pond system. 
   Still referring to  FIG. 9 , the flow control system  21   e  operates in a similar manner as described above, with slight modifications. The flow control system  21   e  provides a flow control module  22   e  and a water receiving component  24   e.    
   As shown in  FIG. 11 , there is a cross-sectional horizontal view of the flow control module  22   e . The flow control module  22   e  comprises a buoyant member  62   e  encased within the housing  71   e . In general, the buoyant member  62   e  functions in a similar manner as the buoyant members with similar numerals described above where the main function of the buoyant member is to provide a consistent water level within the chamber  41   e  described immediately below. The buoyant member  62   e  can be secured to the upper portion of the housing  71   e  by means of a fastener  83   e . Further, the fastener  83   e  can be provided with an upper eye member. 
   The housing  71   e  has an inner surface  81   e  that is adapted to define an interior chamber region  41   e . The interior chamber region is provided with a first vent  87   e  that allows the pressure within the chamber  41   e  to be at a consistent level which in this form is atmospheric pressure. The lower portion of the housing  71   e  is adapted to engage the upper region of the water receiving component  24   e  which in a preferred form comprises the vertical displacement system  70   e  which is a bellow member  80   e  that is best shown in  FIG. 10 . The bellow member  80   e  is similar to that as shown in  FIG. 1 , except the interior tube  70  of  FIG. 1  is not provided in the embodiment as shown in  FIGS. 9–12 . Rather the bellow  80   e  allows the flow control module  22   e  to reposition vertically to a variety of heights as shown in  FIG. 9  and  FIG. 10 . The flow control module  22   e  can reposition laterally a slight amount in this configuration; however, present analysis indicates that the bellow  80   e  which is the primary operating member of the vertical displacement system  70   e  tends to fold up upon itself and stack in a manner as shown in  FIG. 9  without toppling the flow control module  22   e . In a preferred form, the bellow  80   e  has a diameter that is at least one third of the diameter of the flow control module  22   e  (and more specifically the housing  71   e  as shown in  FIG. 11 ). A more preferred range is to have the diameter of the bellow  80   e  to be approximately one half or greater than the diameter of the flow control module  22   e.    
   The vent  89   e  as shown in  FIG. 11  is adapted to communicate with the interior chamber region of the water receiving component  24   e  which in this embodiment is the interior chamber defined by the interior surface of the bellow  8   e   0 . In general, as described in more detail above, the flow control is a function of the input and output pressures and entrance and exit regions of an orifice. A simple method of control of the pressure within the interior chamber  41   e  (the entrance region of the orifice) and the interior chamber of the bellow  80   e  (the exit regions of the orifice) is to have both regions at atmospheric pressure. Of course other methods to adjust the pressure to calibrate the flow can be employed; however, a simple reliable model is to vent both chamber areas to atmospheric pressure so the flow can be solely calibrated upon the resting water level  31   e  within the interior chamber  41   e  and the cross-sectional area flow control orifice  44   e  (see  FIG. 11 ). 
   It should further be noted that in the various embodiments disclosed herein, a mean temperature viscosity of the water passing through the flow control orifice is preferably used. In other words, depending upon the region of the installation, a desirable temperature that would occur during a heavy downpour time of year should be used to calculate the viscosity for the proper fluid flow rate given the head pressure of the control type and the orifice size. 
   The operation of the embodiment as shown in  FIGS. 9–12  is of a similar operation as described in the various embodiments above.  FIG. 10  shows an extreme flow situation where the water level  33   e  is very high within the pond in the control structure  28   e . In this scenario not only is there flow through the flow control module  22   e  down along the water receiving component  24   e , but further there is flow through the first and second fluid passages  86   e  and  88   e .  FIG. 9  shows a minimal flow or no flow situation where the water level  35   e  is at a lower level and just at a drainage point over the upper initial crust portion of the drainage line  95   e . Absent evaporation issues or additional fluid passageways to empty the control container  28   e , this would be the lowest level where at this point, the flow is actually controlled by the water level height  35   e  with respect to the lowest portion of the drainage line  95   e  in communication with the water level. However, as the appreciable amount of flow enters the control container  28   e  by the passageway (not shown) from the adjacent pond, the flow would be controlled by the flow control system  21   e.    
     FIG. 12  shows a partial cross-sectional top view of the flow control assembly  20   e  taken at line  12 — 12  of  FIG. 9 . As can be seen in this figure, the fluid passages  86   e  and  80   e  can be positioned at various angles with respect to the center axis of the flow receptacle  33   e . The passage  37   e  should be of a sufficient strength to support the flow control system  21   e  in the event the water level is drained or evaporated or otherwise below that as shown in  FIG. 9  whereby the entire weight of the flow control system  21   e  is cantilevered thereon. 
   While the present invention is illustrated by description of several embodiments and while the illustrative embodiments are described in detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the scope of the appended claims will readily appear to those sufficed in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants&#39; general concept.