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The digital elevation model data from traditional stereo photogrammetric methods are inade-quate in providing accurate vertical parameters to feed hydrologic models for low-lying, extremely flat areas.High-resolution light detection and ranging (LiDAR) data provide the robust capability of capturing small varia-tions in low-relief playa wetlands. The Rainwater Basin in south-central Nebraska includes a complex of season-ally shallow playa wetlands that attract millions of migratory waterfowl every spring and fall. This researchfocuses on the development of a procedure with applicable protocols to produce LiDAR-derived three-dimen-sional wetland maps and to extract the critical surface parameters (i.e., watershed boundaries, flow direction,flow accumulation, and drainage lines) for playa wetlands. The topo-hydrologic conditions of playa wetlandswere evaluated at the watershed level. The results show that in the Rainwater Basin, 70.7% of the historichydric soil footprints identified in the Soil Survey Geographic (SSURGO) database were not functioning as topo-graphically depressional wetlands. This finding was confirmed by a recent five-year Annual Habit Survey show-ing that 69.8% of the historic hydric soil footprints did not function during the spring migratory bird seasonsbetween 2004 and 2009. The majority of playa wetlands’ topographic conditions have been substantially changedand the SSURGO data cannot fully reflect current topographic reality in the Rainwater Basin.(KEY TERMS: light detection and ranging; Soil Survey Geographic database; historic hydric soil footprint;wetland; playa; Rainwater Basin.)Tang, Zhenghong, Ruopu Li, Xu Li, Weiguo Jiang, and Aaron Hirsh, 2013. Capturing LiDAR-Derived Hydro-logic Spatial Parameters to Evaluate Playa Wetlands. Journal of the American Water Resources Association(JAWRA) 1-12. DOI: 10.1111/jawr.12125INTRODUCTIONThe increased application of Geographic Informa-tion System (GIS) and remote-sensing technologieshas significantly improved the accuracy of spatialparameter modeling (e.g., Wolock and Price, 1994).The United States Geological Survey’s (USGS) 30- and10-m digital elevation models (DEMs) from traditionalstereo photogrammetric methods, however, havecoarse horizontal resolutions and limited vertical accu-racies and thus, cannot be used to capture subtle topo-graphic variations. For example, the vertical accuracyof the 30-m USGS Level 1 DEMs is a minimum of 7 m,with a maximum permitted error of 15 m (Kenwardet al., 2000; Liu and Wang, 2008). The 10-m DEMs

Water erosion processes can significantly affect the delivery and distribution patterns of soil organic carbon (SOC) within the landscape. While many studies focus on the erosion processes and runoff transport of SOC, little attention has been paid to the on-site redistribution and vertical transport of SOC. This study characterizes SOC erosion dynamics, including infiltration-associated movement, and discusses the effects of rainfall intensity and slope position on SOC transport within the hilly red soil region of southern China. The results show that SOC loss was likely due to sediment transport rather than runoff. The eroded SOC was not significantly enriched, which may be due to the soil properties and the type of rainfall event. The initial SOC concentration affected the enrichment ratio of eroded SOC in the sediment. On-site horizontal redistribution occurred regardless of rainfall intensity, whereas the SOC transport trends varied with rainfall intensity and slope positions. This demonstrates that soil preservation could reduce SOC loss, and thus influence the global carbon cycle.

The scale-location specific control on vegetation distribution was investigated through continuous wavelet transforms approaches in subtropical mountain-hill region, Fujian, China. The Normalized Difference Vegetation Index (NDVI) was calculated as an indicator of vegetation greenness using Chinese Environmental Disaster Reduction Satellite images along latitudinal and longitudinal transects. Four scales of variations were identified from the local wavelet spectrum of NDVI, with much stronger wavelet variances observed at larger scales. The characteristic scale of vegetation distribution within mountainous and hilly regions in Southeast China was around 20 km. Significantly strong wavelet coherency was generally examined in regions with very diverse topography, typically characterized as small mountains and hills fractured by rivers and residents. The continuous wavelet based approaches provided valuable insight on the hierarchical structure and its corresponding characteristic scales of ecosystems, which might be applied in defining proper levels in multilevel models and optimal bandwidths in Geographically Weighted Regression.

A 31 year record of ∼44,000 nitrate analyses in ∼11,500 irrigation wells was utilized to depict the decadal expansion of groundwater nitrate contamination (N ≥ 10 mg/L) in the irrigated corn-growing areas of eastern and central Nebraska and analyze long-term nitrate concentration trends in 17 management areas (MAs) subject to N fertilizer and budgeting requirements. The 1.3 M contaminated hectares were characterized by irrigation method, soil drainage, and vadose zone thickness and lithology. The areal extent and growth of contaminated groundwater in two predominately sprinkler-irrigated areas was only ∼20% smaller beneath well-drained silt loams with thick clayey-silt unsaturated layers and unsaturated thicknesses >15 m (400,000 ha and 15,000 ha/yr) than beneath well and excessively well-drained soils with very sandy vadose zones (511,000 ha and 18,600 ha/yr). Much slower expansion (3700 ha/yr) occurred in the 220,000 contaminated hectares in the central Platte valley characterized by predominately gravity irrigation on thick, well-drained silt loams above a thin (∼5.3 m), sandy unsaturated zone. The only reversals in long-term concentration trends occurred in two MAs (120,500 ha) within this contaminated area. Concentrations declined 0.14 and 0.20 mg N/L/yr (p 20 years of management. Average annual concentrations in 10 MAs are increasing (p

TransCanada's proposed international crude oil pipeline route over sensitive, relatively pristine, subirrigated land underlain by the Ogallala aquifer led to increased scrutiny and eventual rejection of the Keystone XL pipeline. Pipeline routing could be made much more acceptable by adopting risk-managed routes that lessen the potential to adversely impact high-quality groundwater and, should a release occur, decrease the longevity of hazardous groundwater contaminants. Threats to water quality are taken quite seriously in states like Nebraska where 85% of the population depend on groundwater for potable water.