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Probabilistic Rainfall/Flood Estimation
Published in Monzur A. Imteaz, Urban Water Resources, 2019
This method analyses maximum discharge in each year of record from a particular river/stream section. It estimates the probability that a maximum flood discharge may exceed a particular magnitude in a year, or in other words, it is the average period between years where the specified maximum discharge is exceeded once. In short, it is also called “Annual Series Analysis”. To perform this analysis, it requires the extraction of maximum discharge from each year from a historical record of many years. It is to be noted that the considered year can comprise of months from January to December, or water year (as it is practiced in some countries, and not starting from January). For such analysis, the number of years for the analysis is equal to the records available for the analysis. For example, Table 3.2 shows several flood estimates for the mentioned years.
Water Quality Modeling and Mapping using Landsat Data
Published in Caiyun Zhang, Multi-sensor System Applications in the Everglades Ecosystem, 2020
The capability of Landsat for salinity modeling and mapping was first examined in northeast Florida Bay, as shown in Figure 7.1. The northeastern bay area comprises the discharge locations of the wide C-111 canal and Taylor Slough carrying a large volume of fresh water entering the bay, which makes its water mass different from that of its surroundings. Data include field-surveyed salinity data and Landsat TM images collected over the northeastern Florida Bay. The USGS developed a project “Monitoring and Assessment Plan” (MAP) as the primary tool for assessing the system-wide performance of CERP over the Everglades. MAP has been operating and maintaining monitoring stations and performs salinity surveys based on boat-mounted systems along the southwest coast of Everglades National Park, the Everglades wetlands, coastlines of northeastern Florida Bay and northwest Barnes Sound. For the boat-mounted systems, salinity is measured along several predesigned transects using a YSI water quality monitor. Position is determined using a GPS unit that interfaces with the YSI monitor. Data collection occurs every 5 seconds and is stored in the YSI 650 data acquisition system. All salinity meters are checked in known conductivity standards prior to and following all surveys. The surveyed data are posted on the website of SOuth Florida Information Access (SOFIA, http://sofia.usgs.gov/). The collected salinity data are available for Water Year 2004–2006 during which 12 boat-based surveys were conducted. The USGS defines Water Year as the 12-month period from October 1 of one year to September 30 of the following year and designates it by the calendar year in which it ends.
How important are climate change and foreseen engineering measures on the sediment dynamics in the San Francisco Bay-Delta system?
Published in Fernanda Minikowski Achete, Multiple Scales of Suspended Sediment Dynamics in a Complex Geometry Estuary, 2020
The Mediterranean climate dictates the seasonal variability, with the rainfall concentrated in the wet winter months from October to April decreasing towards the summer with September the driest month (Conomos et al., 1985). Water year (WY) is defined from 1 October to 30 September to keep the entire wet season in one hydrological year. The seasons modulate the Delta discharge from low values in dry summer months of 50–150 m3s−1 and to wet spring/winter peak discharges of 800–2500 m3s−1. Apart from the intra-yearly seasonality the Delta experiences interannual variability with wetter (2011) and drier years (2013).
Regional variability and changing water distributions drive large-scale water resource availability in Alberta, Canada
Published in Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2023
Brandi W. Newton, Nadine Taube
Daily streamflow data for 32 regulated and 45 unregulated hydrometric stations were downloaded from the Water Survey of Canada (WSC) HYDAT database using the ‘tidyhydat’ package for R (Albers 2017). These stations report continuous data and have streamflow records available for 1976-2015. Stations were selected that have minimal missing data (< 5% missing). When daily data was missing, the overall mean of flow on that Julian day (1976-2015) was substituted. For example, if Julian day 300 was missing in 1978 at a station, the overall average (1976-2015) flow for day 300 at that station was substituted for that day. There was no one day that was always missing and with most data missing during the winter months when flows are not particularly variable, this substitution was considered appropriate. Analyses were calculated for water years (October-September) as this captures the effects of winter snowpack storage on annual streamflow, particularly for mountain headwaters. There is evidence that a portion of warm season groundwater recharge in alpine environments is held in storage until the following winter (Jasechko 2016; Campbell and Ryan 2021) creating a lag beyond the hydrologic year. However, this flow contribution is considered relatively consistent year to year (Paznekas and Hayashi 2016; Hayashi 2020) and is not expected to affect annual streamflow variability.
Assessing annual, seasonal and spatial trends in copper sediment concentrations from a California agricultural waterbody
Published in Journal of Environmental Science and Health, Part A, 2022
Lenwood W. Hall Jr., Ronald D. Anderson
Annual precipitation data (defined as Water Years) from 2011 to 2015 from Cache Slough were summarized to determine the possible influence of precipitation on copper concentrations (Table 3).[21] The 2011 and 2015 data were included to have annual data both before and after the 2012 to 2014 sampling period. Monthly precipitation summary data for water years 2011-2015 for long-term National Weather Service (NWS) precipitation station SACRAMENTO 5 ESE was used for the analysis. This Station location (Lat: 38° 33′ N Lon: 121° 25′ W) is approximately five miles east south east of downtown Sacramento. SACRAMENTO 5 ESE is ∼25 miles from the center of all 12 Cache Slough sample stations and was chosen because it lies at the approximate center of the near upstream watershed. It was also the closest long-term site in the NWS database with five years of uninterrupted rain data by month. A water year starts on October 1 of the previous reference year and ends on September 30 of the reference year. For example, the 2012 Water Year begins on October 1, 2011 and ends on September 30, 2012.
Hydrological perturbations drive rapid shifts in phytoplankton biodiversity and population dynamics in Butte Lake (Lassen Volcanic National Park, California)
Published in Lake and Reservoir Management, 2018
Sampling conducted at Butte Lake was part of a larger project investigating diatom community composition and paleolimnology of several LAVO lakes, and was limited by overall project design, funding, and permitting. Initial reconnaissance was conducted at Butte Lake on 8 January 2012 and on 21 June 2012, but because permitting and funding were not yet fully in place, sampling could not be conducted until August 2012. After the permitting was in place, the lake was sampled on 5 dates (8 Aug 2012, 9 Aug 2013, 31 May 2014, 6 Aug 2014, and 27 Sep 2014) to get a snapshot of August variability and variability over several months of the main algal growing season (spring–fall) in the lake. A water year is defined as including precipitation occurring between 1 October (year previous) and 30 September of the calendar year in which it ends. Our sampling dates capture 2 back-to-back years that include a relatively wet water year (2012) and the driest water year (2013) data available for the 119 yr observation record in California (Swain et al. 2014; Fig. 2). Unfortunately, both permitting and funding ended before the 2015 water year, and no data are reported for the last El Niño year.