{"id":83,"date":"2015-06-09T02:36:28","date_gmt":"2015-06-09T02:36:28","guid":{"rendered":"https:\/\/wireless-telemetry.com\/blog\/?p=83"},"modified":"2015-06-09T02:36:28","modified_gmt":"2015-06-09T02:36:28","slug":"levee-district-control-ditch-and-river-level-sensing","status":"publish","type":"post","link":"https:\/\/wireless-telemetry.com\/blog\/?p=83","title":{"rendered":"Updated – Levee District Control: Ditch and River Level Sensing"},"content":{"rendered":"

Jim Mimlitz, NRI<\/p><\/div>Since 1904, The Des Moines & Mississippi Levee District #1 has provided flood and irrigation control along the Mississippi River near Alexandria Missouri\u00a0through a series of engineered levees, ditches, and pumps. They are guided by a 5-member Board of Directors, and design services are provided by Klingner & Associates Engineers (Quincy, IL)<\/a>.<\/p>\n

Since 2012, Navionics Research has been proud to serve the District as its Control Systems Integrator.\u00a0 The on-site monitored and controlled equipment includes level-sensing instrumentation, two 400 HP pumps and associated variable-frequency drives, power & voltage meters, and a rainfall analyzer.\u00a0 Through the control system user interface, District personnel are able to monitor the status and operational history;\u00a0and they also\u00a0receive cell phone text message and email alarms for key events, such as a pump turning ON\/OFF, high water level detected, or a power failure.<\/p>\n

\"Pumping<\/a>

Pumping Station. Levee (Center), Ditch (Right), Canal to River (Left).<\/p><\/div>\n

A key to the system’s efficient operation is\u00a0accurate and reliable measurement of water levels\u00a0in both the ditch\u00a0and the river.\u00a0 The level of water in the ditch is important, as the pumps are directed to turn ON when the ditch reaches a high-level threshold and OFF when the ditch reaches a low-level threshold.\u00a0 The level of water in the river is also important, as certain pumps are limited\u00a0to a restricted head pressure range.\u00a0 And both levels, when combined with pump speed, pump curve, and system curve information, can be used to estimate rate of flow and totalization.\u00a0 However that topic is worthy of a future article<\/a>, and therefore will not be further addressed here.<\/p>\n

There are\u00a0various instrumentation\u00a0methods available to monitor the water levels.\u00a0 However, this paper will focus on a Pneumatic Bubbler Transducer method.\u00a0 Our method utilizes a pneumatic pump, air sensing lines, transducers, and valve & control components.<\/p>\n

The\u00a0submerged transducer method, which was initially installed at the Levee District,\u00a0but\u00a0recently replaced\u00a0during an upgrade, suffers from\u00a0several disadvantages.\u00a0 First, the submerged transducers are\u00a0generally staged at significant distances from the Control Building, and so\u00a0they tend to be more susceptible to lightning damage and ground loops.\u00a0 Also, any electronic instrument that is submerged in\u00a0water\u00a0has the potential to suffer from water ingress eventually<\/em>, even if the device is IP68-rated <\/a>and designed for that purpose.\u00a0 Furthermore, the use of a submerged transducer\u00a0requires a skilled installation contractor who understands the potential pitfalls and how to avoid them.<\/p>\n

The Pneumatic Bubbler Transducer method does not require an IP68-rated pressure transducer, as the transducer is installed within the\u00a0dry environment of the Control Building.\u00a0 Also, the pressure transducers are installed within the same cabinet (or near) the main controls, and therefore the risk of lightning damage and ground loops is abated.\u00a0 The following diagram illustrates the operation of a Pneumatic Bubbler Transducer level sensing system:<\/p>\n

\"Level<\/a>

Level Sensing — Based Upon Polyethylene Tubing-Based Bubbler System<\/p><\/div>\n

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The following photos\u00a0show the Pneumatic Instrumentation, which was packaged within a dedicated enclosure, and connected to the main control panel:<\/p>\n

\"Pneumatic<\/a>

Pneumatic Pump, Transducers, Valves, and Controls.<\/p><\/div>\n

 <\/p>\n

\"Controls<\/a>

Controls and Telemetry Package. Note the relative simplicity of the wiring due to a high-degree of networked, distributed instrumentation<\/p><\/div>\n

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\"Pressure<\/a>

Pressure Transducers: Keller ValueLine, 0-15 PSIG. Signal Output: 4-20mA<\/p><\/div>\n

Installation\u00a0Photos…<\/p>\n

\"Installation<\/a>

Installation of the Polyethylene Tubing into the Ditch-Side Stilling Well. Jim Mimlitz, Navionics Research (left), Hank Borrenpohl, Okawville Electric (right).<\/p><\/div>\n

 <\/p>\n

\"The<\/a>

The End of the Polyethylene Tube Is Weighted So As Not To Float When Filled With Air.<\/p><\/div>\n

 <\/p>\n

\"Ditch-Side<\/a>

Ditch-Side Stilling Well After Installation of Tubing.<\/p><\/div>\n

 <\/p>\n

\"Installation<\/a>

Installation of the River-Side Tubing. Hank Borrenpohl, Okawville Electric.<\/p><\/div>\n

 <\/p>\n

\"River-Side<\/a>

River-Side Sensing Tube, Post-Installation. Note the Visible Flow from the Pump Discharge Pipe.<\/p><\/div>\n

 <\/p>\n

\"Telemetry<\/a>

Telemetry Display Shows Realtime Performance Data.<\/p><\/div>\n

 <\/p>\n

\"Telemetry<\/a>

Telemetry History Charts. Performance Is Shown A Few Days After Installation of the Pneumatic Bubbler Level Sensing Improvements.<\/p><\/div>\n

 <\/p>\n

It is\u00a0important to note\u00a0that this measurement technique could be applied not only to Levee District controls, but to potable water, as well.\u00a0 For example, for surface-water-based potable water plants, this system could be used to monitor the lake or river level at the raw water intake.\u00a0 For well-based potable water plants, this system could be used to monitor the water table level within the wells. \u00a0In either case, when the measured level\u00a0is too low,\u00a0the controls would be programmed to automatically shut down the pump(s) in order to prevent pump cavitation. \u00a0Another potential application of this system would be to monitor the liquid levels within chemical tanks at filtration\/treatment plant facilities.<\/p>\n

Notable improvements which were made\u00a0after the initial installation include:<\/p>\n