Seepage Detection and Characterization in a Truckee Canal Site using L-band Synthetic-Aperture Radar (SAR) Technology

Project ID: 19258
Principal Investigator: Jong Kang
Research Topic: Condition Assessment
Funded Fiscal Years: 2019 and 2020
Keywords: None

Research Question

1-Can SAR satellite remote sensing technology serve as a new enhanced seepage detection technique for identification of potential seep locations at canal embankments and levees?

2-Can the initial proof-of-concept effort help show that the SAR satellite remote sensing technology will help to inform quantified seepage loss modeling efforts at canal sites? Specifically, is SAR time-lapse response data analysis a feasible approach to help parameterize hydraulic conductivity modeling at various locations along the canal or to give more qualitative information related to lateral changes in canal performance/water losses?

3-Do the results of time lapse analyses for change detection based on the coordinates of known seeps and corresponding dates of canal watering-up/de-watering correlate well with the changes of SAR image data at known seep locations?

4-What is the suitable resolution of the SAR and how small an area of seepage losses can be or not be identified using the SAR image data?

5-Do the volumetric water contents estimated from SAR image data correlate with field and laboratory testing data obtained from soil samples collected at known seepage loss areas?

6-Does the 6-day periodicity of global SAR data coverage offer a sufficient temporal resolution to capture time-lapse responses following operations events (i.e., a subsequent "breakthrough curve" of soil moisture responses following watering up of the canal), in order to capture a seepage-response process and to help reasonably inform subsequent hydrologic modeling and estimation of hydraulic permeability and water loss volumes/rates? If so, what are realistic limitations of this SAR technology and associated 6-day periodicity, in terms of applicable embankment geometries, hydraulic loading conditions, and average hydraulic conductivities needed to make use of this time-lapse analysis approach for estimation of hydraulic conductivity?

Need and Benefit

Reclamation alone holds tens of thousands of miles of in-service water conveyance canals within its infrastructure
inventory. Many of these canal systems have aged beyond their original intended life-span, are showing signs of
aging and disrepair, extensive seepage and embankment failure events are becoming increasingly common, and
consequences of canal failures within urban corridors are constantly increasing due to urban encroachment on these
water conveyance structures. In addition to the problem of increased risk related to canal embankment failures,
concentrated and distributed seepage poses a major challenge to water conservation due to significant water
conveyance system losses. An ongoing need to identify and comprehensively characterize and quantify canal
seepage, both for safety-related and water conservation efforts, is the main motivation for this proposed research.
Existing capabilities of Reclamation team members include field and lab data collection and analysis expertise,
modeling expertise, required background/supportive data and information knowledge and access, and site-specific
knowledge and access permissions. Non-Reclamation team members will bring SAR data analysis expertise, and
hydrologic modeling expertise, and access to critical and supportive data and prior/ongoing research results.
This is cutting-edge seepage-related research that makes use of interdisciplinary collaborative research coordination
with top scientists within each participating field.
If found feasible for seepage detection and characterization, this research could lead to the ability for Reclamation to
1) quickly and effectively identify previously unknown seepage areas on a system-wide or even nation-wide scale, 2)
monitor known seepage areas for disconcerting changes, 3) help to quantify system-wide water conveyance losses
and identify priority sections for focused maintenance efforts, 4) differentiate between suspected seepage and natural
groundwater drainage phenomena not related to canal water losses, 5) evaluate canal liner performance based on
pre/post installation seepage levels, 6) evaluate canal damage repair and other proactive maintenance activities (e.g.,
berm installations) based on pre/post seepage conditions, 7) identify changes in seepage following standard canal
dredging activities, which have occasionally been suspected of initiating or exacerbating seepage losses, 8) identify
other structures/areas/phenomena that could be better characterized using this technology.
Assuming that SAR technology is a feasible tool for seepage detection and characterization, by not funding this
research, Reclamation would be missing out on a 1) an opportunity to collaborate with NASA scientists actively
pursuing this application/topic, and 2) a lot of insightful data and knowledge, in terms of canal system performance
and health (both from a static and time-lapse monitoring analysis standpoint).
Benefit/cost analysis could be performed to justify widespread adoption of this relatively inexpensive technology
relative to 1) the annual costs of visual inspections and unnecessary or ineffective maintenance repair efforts, 2)
associated costs/risks that are incurred due to the levels of uncertainty surrounding canal seepage and water
conveyance losses using standard inspection and field surveying approaches, 3) costs associated with canal failure
events resulting from inadequate seepage detection and mitigation efforts, 4) costs and uncertainties/limitations
associated with more spatio-temporally sparse efforts for data collection/monitoring of canal losses.

Contributing Partners

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Research Products

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Last Updated: 4/4/17