I bumped into the WaterWired blog today. I also bumped into this blog while trying to determine the correct spelling(s) of ground water. I'm still slightly uncertain.
The same thing happened earlier this year when I started reading about stream gauges. USGS seems to favor "gage", at least on this part of their website.
Monday, August 24, 2009
Monday, August 10, 2009
Town of Cary Storm Drain Stenciling
PIV Research In Iowa - Need for Image-based Stream Stage Cited
The Iowa Institute of Hydraulic Research and Department of Civil and Environmental Engineering has been conducting exciting research with Particle Image Velocimetry methods. Engineers and Scientists in Iowa, in collaboration with others, have taken a well-established laboratory measurement method to a field setting. [1] Particle Image Velocimetry (PIV) uses mass conservation principles to determine the velocity of particles moving through a given region.[1]
Because they are looking at water in natural settings, they are experiencing some of the challenges we expect to face with the GaugeCam project. The effects of variable lighting, glare and shadows must be addressed.[2] Wind and rain effects are also concerns.[2] In addition, PIV requires observable particles, whether natural or seeded. [1] In some cases, natural occurrences, such as bubbles in the water can be recognized and tracked as particles.[2]
One particular challenge noted by researchers is the incorporation of stage measurement.[3] Specifically, stage measurement using image-based techniques is mentioned as an ideal solution because an image-based solution could utilize the same type of data transmission as the PIV camera system. [3]
References
[1] Bradley, A. A., Kruger, A., Meselhe, E., & Muste, M. (1999). Low flow measurement in streams using video imagery. Water Resources Research,
[2] Creutin, J. D., Muste, M., Bradley, A. A., Kim, S. C., & Kruger, A. (2003). River gauging using PIV techniques: A proof of concept experiment on the Iowa river. Journal of Hydrology, 277(3), 182. doi:10.1016/S0022-1694(03)00081-7
[3] Hauet, A., Kruger, A., Krajewski, W. F., Bradley, A., Muste, M., Creutin, J., et al. (2008). Experimental system for real-time discharge estimation using an image-based method. Journal of Hydrologic Engineering, 13(2), 105-110. doi:10.1061/(ASCE)1084-0699(2008)13:2(105)
Because they are looking at water in natural settings, they are experiencing some of the challenges we expect to face with the GaugeCam project. The effects of variable lighting, glare and shadows must be addressed.[2] Wind and rain effects are also concerns.[2] In addition, PIV requires observable particles, whether natural or seeded. [1] In some cases, natural occurrences, such as bubbles in the water can be recognized and tracked as particles.[2]
One particular challenge noted by researchers is the incorporation of stage measurement.[3] Specifically, stage measurement using image-based techniques is mentioned as an ideal solution because an image-based solution could utilize the same type of data transmission as the PIV camera system. [3]
References
[1] Bradley, A. A., Kruger, A., Meselhe, E., & Muste, M. (1999). Low flow measurement in streams using video imagery. Water Resources Research,
[2] Creutin, J. D., Muste, M., Bradley, A. A., Kim, S. C., & Kruger, A. (2003). River gauging using PIV techniques: A proof of concept experiment on the Iowa river. Journal of Hydrology, 277(3), 182. doi:10.1016/S0022-1694(03)00081-7
[3] Hauet, A., Kruger, A., Krajewski, W. F., Bradley, A., Muste, M., Creutin, J., et al. (2008). Experimental system for real-time discharge estimation using an image-based method. Journal of Hydrologic Engineering, 13(2), 105-110. doi:10.1061/(ASCE)1084-0699(2008)13:2(105)
Monday, July 13, 2009
Monday, June 22, 2009
Christian Sets up Server
Christian and I had a good day at NCSU today!
Without going into details (many of which I don't understand), Christian set up this computer in the lab so we can access it remotely. Ken will be able to view images, etc, that appear on this computer while sitting at home.
While we have the computer and basic configuration in place, Christian has a good bit of detail work to finish. That's the cool part about remote access; he can work on it from home now!
The camera is the next major piece of hardware to put in place.
Christian really did all the work, as you can see:
Without going into details (many of which I don't understand), Christian set up this computer in the lab so we can access it remotely. Ken will be able to view images, etc, that appear on this computer while sitting at home.
While we have the computer and basic configuration in place, Christian has a good bit of detail work to finish. That's the cool part about remote access; he can work on it from home now!
The camera is the next major piece of hardware to put in place.
Tuesday, June 9, 2009
Water Level Measurement Software
Ken has created this interface for managing images. He says there's a lot more work to do on the software infrastructure to support this, but it's always nice to see the tangible parts!
Friday, June 5, 2009
Hydrometry - Pressure Transducers
Quite a few days have passed since my last post about water level instrumentation, so I should probably mention my source again. Hyrdrometry, 3rd Edition, by Wubbo Boiten. (You can go read the archives if you want an official MLA style citation.) All of the pressure transducer material is based on pages 8-9.
- Pressure Sensors
- Pressure Probes
- Pressure Transmitters
Function:
The basic function of a pressure transducer is to take pressure and turn it into an electric signal. The electric signal is processed, combined with known information about the water density, and converted to a height measurement. The height measurement is typically recorded on a data logger.
Here's a schematic:
Error:
There are a couple sources of error associated with pressure transducers:
1.) Air pressure above the water must be accounted for
2.) Since the pressure transducer is measuring pressure and converting it to water depth, the density of the water is a critical parameter. For instance, salt water has a different density than fresh water. Cold water has a different density than warm water.
Other Concerns:
Pressure transducers may be damaged if exposed to extreme pressures.
Characteristics:
Range: 0-40 feet
Accuracy: 0.1% of the full range
Pressure Transducers:
Three other names commonly used for pressure transducers:- Pressure Sensors
- Pressure Probes
- Pressure Transmitters
Function:
The basic function of a pressure transducer is to take pressure and turn it into an electric signal. The electric signal is processed, combined with known information about the water density, and converted to a height measurement. The height measurement is typically recorded on a data logger.
Here's a schematic:
Error:
There are a couple sources of error associated with pressure transducers:
1.) Air pressure above the water must be accounted for
2.) Since the pressure transducer is measuring pressure and converting it to water depth, the density of the water is a critical parameter. For instance, salt water has a different density than fresh water. Cold water has a different density than warm water.
Other Concerns:
Pressure transducers may be damaged if exposed to extreme pressures.
Characteristics:
Range: 0-40 feet
Accuracy: 0.1% of the full range
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