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Marcella Appel

Publications and source records attributed to Marcella Appel.

3 recordsLinked to original sources
USGS2025

Relationships between water quality, stream metabolism, and water stargrass growth in the lower Yakima River, 2018 to 2020

Since the early 2000s, water clarity on the lower Yakima River has improved. Changes in best management practices combined with a total maximum daily load for suspended sediment led to these improved conditions. As water clarity improved, so did conditions for aquatic plants; the clearer the water, the better the light penetration, and dramatic increases in plant biomass were observed. In the lower Yakima River, beds of native water stargrass (grass-leaf mud-plantain, Heteranthera dubia) are prolific and can extend bank to bank in some locations. Increased primary productivity can alter local water quality by increasing daily swings of dissolved oxygen (DO) and pH from photosynthesis. In this study, we collected continuous water quality data for 2.5 years at three sites on the lower Yakima River to provide a detailed examination of water quality conditions. These sites were located just below the Prosser Dam (Prosser site, USGS station 12509489), at a long-term USGS streamgage in Benton County (Kiona site, USGS station 12510500), and in West Richland, WA (Van Giesen site; USGS station 12511800). In addition to the continuous water quality data collected, estimates of water stargrass biomass were made through the growing season (June through September) during water years 2018–2020. The main objectives of this study were to document water quality conditions on the lower Yakima River and to analyze if there was a statistical relation between the amount of water stargrass biomass and the observed daily cycles of water quality. During summer, frequent exceedances of established water quality criteria were documented each year during this study. Maximum daily temperatures exceeded 21o C, minimum DO concentrations were below 8 milligrams per liter (mg/L), and maximum pH surpassed 8.5 almost every day from June through August each water year across all three monitoring locations. Water stargrass biomass tended to increase from June through August and September but was ‘reset’ by the following summer likely from high winter and spring streamflows and natural die-off. Results from this study suggest that spring peak discharge and average spring discharge affects late-season water stargrass biomass. In 2018, the highest peak discharge of the study took place, and the August water stargrass biomass values were lower in 2018 than in 2019 and 2020. Seven different water quality metrics were computed for a 7-day and 28-day period prior to each water stargrass sample to examine possible correlations between the plant biomass and water quality. We examined daily maximum temperature, DO minimum, DO range, pH maximum, pH range, mean nitrate, and nitrate range. While there were some statistically significant correlations among the seven water quality metrics and median water stargrass biomass, the correlations were not consistent across all three sites. At the Prosser site, the 7-day average daily maximum pH and average daily pH range showed significant correlations with median water stargrass biomass. At the Kiona site, both the 7-day and 28-day mean nitrate values showed a significant relationship to median water stargrass biomass. At the Van Giesen site, there were no significant correlations between the seven water quality metrics and median water stargrass biomass. However, whole-stream estimates of gross primary productivity at the Kiona site, which incorporate the entire river community, were related to temperature, DO, and pH indicating the whole river community is influencing surface water quality to some extent. Additional data on water stargrass biomass and continuous water quality could help elucidate the complex interactions between growth and water quality. At a minimum, collection of water stargrass biomass data near the end of the growing season (mid to late August) could be added to locations where continuous water quality and streamflow discharge measurements are also being collected. In addition, experimental removal of water stargrass and its effects on local water quality could provide insight into the complex relationships between water stargrass growth and water quality. Finally, further investigations into streamflow and its effects on water stargrass could be improved. Our data showed a qualitative relationship between spring peak discharge, average spring discharge, and August water stargrass biomass, but more data are needed to confirm this. If spring high streamflows are important for late-season biomass, then targeted flow releases from reservoirs in the upper watershed could be used to slow down water stargrass growth during summer months.

EarthArXiv↗
USGS2024

Extent and duration of cold-water areas associated with side channels and tributaries of the lower Yakima River, Washington, September 2018–20

Previous work on the lower Yakima River, Washington (downstream from Union Gap), has identified several cold-water areas that could be thermal refuges for migrating salmonids. These cold-water areas are characterized by small tributaries that are typically cooler than the main-stem river during summer months (June–August). Twenty-seven temperature sensors were deployed along the lower 90 miles of the Yakima River at 7 locations where cold water had been previously observed. Deployments lasted from 1 to 2 years from September 2018 to September 2020 to document the extent and duration of these cold-water areas. Cold-water areas included the mouths of tributaries, alongside channels, and alcoves. Throughout summer months, main-stem river temperatures were warm, averaging about 92 days, when maximum daily temperatures exceeded 21 degrees Celsius (°C). The relationship between temperatures in the lower Yakima River and its tributaries varied seasonally; tributary water temperatures were 2–10 °C cooler than the main-stem river during summer months but 6–10 °C warmer than main-stem temperatures during winter months. The cooling effect of tributary inputs reduced downstream temperatures in the main stem by an average of 2–4 °C up to 175 feet downstream from tributary mouths. Side channel locations showed evidence of cooling, most likely from subsurface groundwater seeps, but the magnitude of cooling was less evident compared to tributaries. This study provides new information on spatial and temporal dynamics of cold-water areas on the lower Yakima River, which might provide cold-water habitat for migrating fishes in the future.

Washington↗
USGS2022

Thermal heterogeneity and cold-water anomalies within the lower Yakima River, Yakima and Benton Counties, Washington

Warm water temperatures in the lower Yakima River in central Washington are key limitations to the restoration of Pacific salmon ( Onchorhynchus spp .) populations within the Yakima River Basin. Identification of the location and magnitude of cold-water anomalies, which are cooler than ambient river temperatures during summer months, and the processes that create and maintain them is needed to inform salmon restoration efforts within the Yakima River Basin. Longitudinal thermal profiles of nine reaches in the lower Yakima River were surveyed at ambient river velocity during summer 2018 when surface-water temperatures were near their annual maximum and the difference between surface-water and groundwater temperatures was greatest. The profiles were compared to previously published profiles of the same reaches measured in 2001, 2002, 2008, and 2009, and analyzed in the context of hydrologic, geomorphic, and hydrogeologic conditions that may create and maintain cold-water inputs to the river. Cold-water anomalies that departed from expected diurnal increases in water temperature were measured in all nine study reaches and were attributed to diffuse groundwater discharge through the streambed, discrete groundwater discharge at seeps and springs, and cold-water tributaries entering the river. Some cold-water anomalies were measured during repeated surveys in different years, whereas other cold-water anomalies did not persist across surveys. Additionally, some discrete cold-water anomalies were confined to one side of the channel, but others associated with diffuse groundwater discharge were present across the channel for several river miles. Hydrogeologic conditions including the extent and thickness of aquifers connected to the Yakima River, geomorphic conditions including channel gradient, channel geometry, and floodplain extent, and the location of tributaries, irrigation returns, and other surface-water inputs created the large-scale conditions that facilitate the formation and maintenance of cold-water anomalies. Finer-scale geomorphic features such as side channels, gravel-bar alcoves, deep pools, and other locations, where colder water collected and remained relatively unmixed with upstream surface water, were also important factors in the occurrence and distribution of cold-water anomalies. These hydrogeologic and geomorphic conditions, coupled with the alteration of the Yakima River’s hydrologic regime to support irrigation within the Yakima Valley, contributed to the surveyed distribution of cold-water anomalies within the river.

Washington↗