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1. Changing characteristics of runoff and freshwater export from watersheds draining northern Alaska

   https://doi.org/10.5194/tc-13-3337-2019  

   Rawlins, Michael A.; Cai, Lei; Stuefer, Svetlana L.; Nicolsky, Dmitry (January 2019, The Cryosphere)

   Abstract. The quantity and quality of river discharge in Arctic regions is influenced by many processes including climate, watershed attributes and, increasingly, hydrological cycle intensification and permafrost thaw. We used a hydrological model to quantify baseline conditions and investigate the changing character of hydrological elements for Arctic watersheds between Utqiagvik (formerly known as Barrow)) and just west of Mackenzie River over the period 1981–2010. A synthesis of measurements and model simulations shows that the region exports 31.9 km3 yr−1 of freshwater via river discharge, with 55.5 % (17.7 km3 yr−1) coming collectively from the Colville, Kuparuk, and Sagavanirktok rivers. The simulations point to significant (p<0.05) increases (134 %–212 % of average) in cold season discharge (CSD) for several large North Slope rivers including the Colville and Kuparuk, and for the region as a whole. A significant increase in the proportion of subsurface runoff to total runoff is noted for the region and for 24 of the 42 study basins, with the change most prevalent across the northern foothills of the Brooks Range. Relatively large increases in simulated active-layer thickness (ALT) suggest a physical connection between warming climate, permafrost degradation, and increasing subsurface flow to streams and rivers. A decline in terrestrial water storage (TWS) is attributed to losses in soil ice that outweigh gains in soil liquid water storage. Over the 30-year period, the timing of peak spring (freshet) discharge shifts earlier by 4.5 d, though the time trend is only marginally (p=0.1) significant. These changing characteristics of Arctic rivers have important implications for water, carbon, and nutrient cycling in coastal environments. 

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2. Biogeochemical River Runoff Drives Intense Coastal Arctic Ocean CO ₂ Outgassing

   https://doi.org/10.1029/2022GL102377  

   Bertin, C.; Carroll, D.; Menemenlis, D.; Dutkiewicz, S.; Zhang, H.; Matsuoka, A.; Tank, S.; Manizza, M.; Miller, C. E.; Babin, M.; et al (April 2023, Geophysical Research Letters)

   Key Points Mackenzie River biogeochemical discharge decreases the southeastern Beaufort Sea carbon sink Terrestrial dissolved inorganic carbon (DIC) is the primary driver of outgassing events in the SBS, followed by terrestrial DOC Interannual variability in river discharge modulates localized air‐sea CO 2 flux 

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3. Propagation of future climate conditions into hydrologic response from coastal southern California watersheds

   https://doi.org/10.1007/s10584-019-02371-3  

   Feng, Dongmei; Beighley, Edward; Raoufi, Roozbeh; Melack, John; Zhao, Yuanhao; Iacobellis, Sam; Cayan, Daniel (March 2019, Climatic Change)
4. Urban runoff drives titanium dioxide engineered particle concentrations in urban watersheds: field measurements

   https://doi.org/10.1039/d2en00826b  

   Nabi, Md Mahmudun; Wang, Jingjing; Erfani, Mahdi; Goharian, Erfan; Baalousha, Mohammed (March 2023, Environmental Science: Nano)

   Urban runoff is a significant source of pollutants, including incidental and engineered nanoparticles, to receiving surface waters. The aim of this study is to investigate the impact of urbanization on the concentrations of TiO 2 engineered particles in urban surface waters. The study area boundaries are limited to the Lower Saluda and Nicholas Creek-Broad River from upstream, and outlet of upper Congaree River in Columbia, South Carolina, United States from downstream. This sampling area captures a significant footprint of the urban area of the city of Columbia. Water samples were collected daily from four sites during two rain events. All samples were analyzed for total metal concentrations following acid digestion and for particle number concentration and elemental composition using single particle-inductively coupled plasma-time of flight-mass spectrometry (SP-ICP-TOF-MS). The Ti/Nb ratios in the Broad and Congaree River samples are generally higher than those of natural background ratios, indicating contamination of these two rivers with anthropogenic Ti-bearing particles. Clustering of multi-metal nanoparticles (mmNPs) demonstrated that Ti-bearing particles are distributed mainly among three clusters, FeTiMn, AlSiFe, and TiMnFe, which are typical of naturally occurring iron oxide, clay, and titanium oxide particles, indicating the absence of significant number of anthropogenic multi-element Ti-bearing particles. Thus, anthropogenic Ti-bearing particles are attributed to single-metal particles; that is pure TiO 2 particles. The total concentration of anthropogenic TiO 2 in the rivers was determined by mass balance calculation using bulk titanium concentration and increases in Ti/Nb above the natural background ratio. The concentration of anthropogenic TiO 2 increases following the order 0 to 24 μg L −1 in the Lower Saluda River <0 to 663 μg L −1 in the Broad River <43 to 1051 μg L −1 in Congaree River at Cayce <58 to 5050 μg L −1 in the Congaree River at Columbia. The concentration of anthropogenic TiO 2 increases with increases in urban runoff. The source of anthropogenic TiO 2 is attributed to diffuse urban runoff. This study demonstrates that diffuse urban runoff results in high concentrations of TiO 2 particles in urban surface waters during and following rainfall events which may pose increased risks to aquatic organisms during these episodic events. 

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5. Spatiotemporal variation in runoff and baseflow in watersheds located across a regional precipitation gradient

   https://doi.org/10.1016/j.ejrh.2022.101071  

   Waterman, Breanna Rivera; Alcantar, Gonzalo; Thomas, Samantha G.; Kirk, Matthew F. (June 2022, Journal of Hydrology: Regional Studies)