SAGEEP 2017  in Denver was a great conference!  The weather was gorgeous and the talks were interesting and informative.  Here are some photos from the outdoor demonstration of new geophysical equipment.

New GPR System and a stroller for GPR twins!

Wireless geophones

Electrode switch box for lab resistivity experiments.

The abstract for the paper I presented is provided below.

Date: Wednesday, March 22


Author(s): Jonathan Nyquist, Temple University; Laura Toran, Temple University; Paul O’Neill, Temple University; Kelly Devlin, Temple University


Philadelphia is one of nearly 860 municipalities in the United States that has a combined sewer overflow.  Following major storms, the volume of rainwater runoff to be treated can exceed plant capacity, leading to the discharge of the untreated mixture into local waterways.  Efforts to reduce sewer overflow have focused on increasing stormwater infiltration and broadening the range of stormwater arrival times to lower peak discharge. One research question is the significance of the approximately 40,000 vacant lots in Philadelphia as infiltration hotspots given the uncertainty about the composition and properties of urban soils. To characterize these vacant lots with a sufficient point infiltration measurements to map heterogeneity would be prohibitively expensive and time-consuming. We are evaluating geophysical monitoring as a cost-effective alternative to point infiltration measurements by collecting a series of repeat GPR and terrain conductivity data sets over a small (5 x 15 m) test site at Temple University.  Measurements collected before and after sprinkler irrigation were compared with infiltrometer measurements, higher soil moisture correlated with a depression in the microtopography. The GPR data shows evidence of heterogeneous infiltration, but clay content limited radar utility at this site and is likely to be a problem at most sites in the city. The changes in terrain conductivity over time, which can be modeled to a first approximation as a saturated layer migrating downward, also showed increased infiltration over the micro-depression appears to be the most promising monitoring method.  Future work will include investigation of additional test sites and exploring the role of soil compaction on infiltration, and additional infiltrometer measurements.

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