When you are in the water business for a long time, it is inevitable that you will either be asked or told about the reliability and accuracy of divining rods. I even once had a colleague who, when searching for the edge of water under an ice cover, would use bent coat hangers to locate the edge of the stream bed, so as not to run his ice drill into the rocks. You might think that this USGS paper from 1917 would have put the whole topic to rest long ago, but it hasn’t. People still believe what they want to believe.
Good data from extreme events is rarely the result of good luck. It takes a lot of planning and preparedness to get the right equipment in the right place at the right time. The USGS rapid deployment gauges are a good example of how to be prepared for extreme weather.
Many streams for which we need reliable flow data are nearly impossible to monitor using conventional technology because of bed load movement. The stream geometry is constantly changing, which violates assumptions implicit in the use of either sage-discharge or index-velocity methods. The proposed method of using a combination of Ground Penetrating Radar (GPR) and Surface Velocity Radar (SVR) will likely not be a cheap or easy solution, but it is, at least, a solution. When all else fails, this might be your best bet. The added bonus is that it is non-contact, which is pretty much the only hope for sensor survival in streams that move tonnes of gravel with every storm cycle.
The eight warmest years on record have occurred since 1998. This plot from the World Meteorological Organization puts the first five months of 2017 into perspective, showing that 2017 is on track to be the second warmest year on record, only behind 2016.
WMO SPICE Testing and Development of Precipitation Gauge Adjustments for Undercatch of Solid Precipitation
The World Meteorological Organization (WMO) Solid Precipitation Intercomparison Experiment (SPICE) examined 9 different combinations of precipitation gauges/shields in several different environments. They then tested different functions for correction of the data for undercatch of solid precipitation. The use of high efficacy shields results in smaller uncorrected biases and higher number of 30 minute events with errors less that 0.1 mm. It appears as if there is error enhancement from correction of unshielded gauges – at higher wind speeds where measurements need doubling or tripling, the measurement uncertainty is doubled or tripled accordingly. This should be no surprise to readers of Hydrology Corner – the best way to control the quality your data is with best practices in the field.
A recent survey shows that Canadians care more about issues such as education and healthcare than they do about water. However, in the event of an emergency, water is the most important thing that Canadians care about. I think it is precisely because safe and abundant water is so readily available that it is such a low priority for day-to-day living. Also, I think it is interesting to see that in a natural disaster, Canadians would ensure that they have access to water above all else. This implies a need for self-reliance. If Canadians thought that a 911 call would protect them, they would have ranked communication much higher.
Remote sensing of water quality from satellite observations needs validation in terms that are readily understandable in the context of human observations. In particular, it is best if the observations are intuitive and thus resonate with lived experience. NASA’s novel solution to this is “Fowler’s Sneaker Depth” – the depth to which a person can still see the tops of their white sneakers when standing in the water.
The “Dirty Dozen” of Freshwater Science: Detecting Then Reconciling Hydrological Data Biases and Errors
This is essential reading for anyone using or producing hydrometric data. These twelve examples illustrate how data, for want of effective data and metadata management, can be disinformative rather than informative. Data users need to read this to learn what tests to perform and what questions to ask of their data. Data producers need to read this to learn how to prepare and present their data in a way that prevents misuse and misunderstanding.
Discharge derived from rating curves are used to link the forecast future with the reality present. However, uncertainties in the rating curve may result in a poor estimate of present reality. The authors investigate the effect of rating curve uncertainty on flood forecast performance and conclude that models with uncertainty have low sensitivity to threshold exceedances used for flood warning. Well-defined stage-discharge curves based on a large range of flow observations (i.e. curves with low uncertainty) are recommended for operational flood forecasting sites.
The risks and impacts of a 1- or 2-m sea level rise differ substantially for coastal cities and island nations. But perhaps even more important for planning is whether that flooding occurs in 2050 or 2150. This question can only be addressed by constraining the rates of ice loss, which must be a top research priority. Determining ice loss rates requires continued development of monitoring capacity, a sustained focus on process studies, and further integration of observations and modeling efforts.”
The WMO has announced YOPP – the year of polar prediction – from mid-2017 to mid-2019 as a campaign to improve predictions of weather, climate, and ice conditions in the Arctic and Antarctic. The Arctic and parts of the Antarctic are heating twice as rapidly as the rest of the world, causing melting of glaciers, shrinking sea ice and snow cover. Warming arctic air masses and declining sea ice are believed to affect ocean circulation and the jet stream, and are potentially linked to extreme phenomena such as cold spells, heat waves and droughts in the northern hemisphere.
A streamflow and precipitation reconstruction study spanning 445 years in the Upper Rio Grande basin demonstrates the role of temperature in the runoff ratio – the percentage of precipitation that becomes streamflow. This result seems obvious but it is a good reminder that the hydrological cycle is the product of both a water balance and an energy balance.
The WMO has produced a short (4:47) video explaining how meteorologists contribute to society.
This new report from the World Bank addresses the importance of using water as a path toward resilience and stability. The report identified three mechanisms linking water insecurity to fragility: (1) failure to provide citizens with water services; (2) failure to protect citizens from water-related disasters; and (3) failure to preserve surface, ground, and transboundary water resources. For water security to continue to be central to poverty reduction efforts and development, water-related investments need to increasingly address compound risks arising from fragility, conflict, and violence.
Most bridges are built to a 100-year design event. In this study of 35 bridge failures 23 collapsed at flows with a return period of less than 100 years. This result points to a need for better data-driven methods for evaluating engineering risk. The prevailing use of a single design statistic is insensitive to climate, land-use and streamflow regulation change on hydraulic bridge collapse risk.