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22-2. Characterizing connectivity of natural and anthropogenic headwaters to develop a regional-to-national geospatial fabric capable of identifying watershed sensitivity to climate and human drivers

Headwater and flowpath configurations are basic elements in understanding, modeling, and managing watershed-scale hydrologic and geomorphic processes. We seek a Mendenhall to map and quantify headwaters into a geospatial fabric involving recent advances in landscape-scale characterization of waterbodies to develop computational capabilities and advance process understanding of hydrologic networks.

Description of the Research Opportunity

The spatial allocation and extent of contributing waters extending beyond the CONUS channel network (hereafter headwaters) affect watershed properties as well as in-stream erosion, water quality, ecosystem, and other landscape characteristics. Headwater regions are extremely diverse, and are major contributors to runoff, perennial flow, sedimentation, and nutrient and pollutant loads in downstream areas. Recent research efforts demonstrate the critical need for connecting headwaters to downstream perennial streams to understand watershed-scale sediment and phosphorus sources and wetland influences on water quality (Leibowitz et al 2023). Additional studies link changes in headwater wetland storage with headward extension of channels from accelerated geomorphic evolution during extreme floods or human-engineered ditching (Fitzpatrick et al., 2023). Anthropogenic ditches and sub-surface tiles that drain wetlands and saturated soils are one of many human-influenced headwater hydrologic characteristics that impact local and downstream conditions. Headwater areas are formed through complex landscape processes, and climate change has potential to influence this dynamic headwater transition from non-channelized waters to channel networks. Snow hydrology and frozen soil in headwaters is another factor that, coupled with a changing climate, is critical to understanding both local off-channel waters and their downstream contributions. The presence or absence of snow versus frozen bare soil has drastic impacts on sediment production, water availability, ecosystem function, and more. In warmer parts of the country, headwaters range from perennial wetlands to high desert. In all cases, the hydrologic and ecosystem characteristics (and feedback between the two) of these areas have major implications for local conditions and further downstream. Building a comprehensive dataset that maps and characterizes hydrologic connections among headwaters and the existing CONUS stream network heralds a better understanding of a wide range of topics. An enhanced NHDPlusV2 network was used in Wieczorek (2018) and was brought forward as a “reference fabric” (Blodgett, 2022), and is currently being integrated with NHDPlusHR to support current Water Mission Area (WMA) projects. It is also forming the basis for many national scope activities within the USGS, at the National Weather Service, and in the broader “Internet of Water” community. NHDPlusHR is also being linked to the reference fabric as part of the related (matching) efforts happening in the WMA National Hydrologic Geospatial Fabric. NHDPlusHR will not be used directly for this work, but results from this project will be linked to NHDPlusHR identifiers for future use.

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.



Blodgett, D.L., 2022, Updated CONUS river network attributes based on the E2NHDPlusV2 and NWMv2.1 networks: U.S. Geological Survey data release,

Fitzpatrick, F.A., Magyera, K., Laumann, J., Larson, C., Rockwood, S., Dantoin, E., Hollenhorst, T., Krumwiede, B., Nelson, B., Prokopec, J., Johnson, K., 2023, Connecting flood-related fluvial erosion and deposition with vulnerable downstream road-stream crossings: Federal Interagency Sedimentation and Hydrologic Modeling Conference (SedHyd) 2023 Conference Proceedings, May 8-12, 2023, St. Louis, MO 206.pdf (

Leibowitz, S.G., Hill, R.A., Creed, I.F., Compton, J.E., Golden, H.E., Weber, M.H., Rains, M.C., Jones, C.E., Lee, E.H., Christensen, J.R., Bellmore, R.A., Lane, C.R., 2023. National hydrologic connectivity classification links wetlands with stream water quality. Nat Water 1, 370–380.

Wieczorek, M.E., Jackson, S.E., and Schwarz, G.E., 2018, Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 3.0, January 2021): U.S. Geological Survey data release,


Possible Duty Station(s)

Location negotiable


Areas of PhD

Geomorphology, geology, geospatial analyses, hydrology and hydraulics modeling, hydrology, ecology or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).



Applicants must meet one of the following qualifications: Research Hydrologist, Research Physical Scientist, Research Oceanographer, Research Engineer, Research Geologist.

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)