Skip to main content

Person

Joshua C Koch

Research Hydrologist
Email: jkoch@usgs.gov
Office Phone: 303-817-5595
Fax: 907-786-7150
ORCID: 0000-0001-7180-6982

Location
4210 University Drive
Anchorage , AK 99508-4626
US
thumbnail
This dataset contains taxonomic information, counts, and lengths of macroinvertebrates collected from rivers in northwest Alaska using drift and kick nets during summer and fall 2015-2019. Version History: First release: February 2024 Revised: August 2024 (ver. 1.1)
thumbnail
Permafrost (perennially frozen) and active-layer (seasonally thawed) soils varying in soil carbon (C) and nitrogen (N) content and radiocarbon age were collected from three sites in interior Alaska to determine potential release of dissolved organic carbon (DOC), total dissolved N (TDN), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (DIN) upon thaw. Soil cores were cut into 15 cm thick sections, and deep active-layer (15-30 cm above the permafrost boundary) and shallow permafrost (15-30 cm below the permafrost boundary) sections were thawed and leached with deionized water. Soil leachates were analyzed for DOC, TDN, nitrate (NO3-), and ammonium (NH4+) concentrations, dissolved organic matter...
thumbnail
High latitude, boreal watersheds are nitrogen-limited ecosystems that export large amounts of organic carbon. Key controls on carbon cycling in these environments are the biogeochemical processes affecting the nitrogen cycle. This data release presents results of a 3-year field study from 2008-2011 to document the relation between seasonal and transport-associated changes in carbon and nitrogen pools within Nome Creek, an upland headwater tributary of the Yukon River, Alaska, and two first order tributaries to Nome Creek, West Twin Creek and East Twin Creek. Stream-water geochemistry was characterized using: a) biweekly sampling at fixed sampling stations to assess changes through the course of a summer season;...
thumbnail
This dataset includes discrete water quality and discharge data for three streams that flow through wetlands. There are two measurement and sampling locations on each stream: one immediately upstream from the wetland and one immediately downstream from the wetland. Measurements and sample collection occurred in 2010 and 2011 at West Twin Creek, AK; in 2019 and 2020 at Allequash Creek, WI; and in 2013, 2014, and 2017 at the Big Thompson River, CO. The upstream and downstream data from Allequash Creek and the Big Thompson River are from established USGS sites. At Allequash Creek, the downstream site is USGS 05357206 Allequash Creek Site No. 3 Nr Boulder Junction, WI, and the upstream site is USGS 5357205 Allequash...
thumbnail
Groundwater Flow and Temperature Modeling to Predict Stream Temperatures in Beaver Creek, Kenai Peninsula, Alaska
Salmon are an important resource to the ecosystems, economy, and culture of the Kenai Peninsula, Alaska. However, salmon are under increasing stress due to warming water temperatures and decreasing stream flow. Groundwater is a major contributor to many streams that can help maintain fish habitat during low flows and contributes cooler water that regulates stream temperatures in the warm summer months. As the climate warms, the ability for groundwater to cool stream temperatures will likely become more critical to streams that are used by salmon, such as Beaver Creek near Kenai, Alaska. Preliminary analysis of historical streamflow data indicates that on average, Beaver Creek receives nearly 80% of its flow...
View more...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.