Climate is defined by the statistics of temperature, humidity, atmospheric pressure, wind and precipitation in a given region. Cold climate hydrology is characterized by high variations in the weather by the seasons, having warmer summers and cold winters.
Cold climate affects the hydrology by changing the hydrological cycle, while the temperature is below zero and surfaces and the ground may freeze. The precipitation occurs in form of sleet and snow, and is be stored in snowpack and often transported by drifting or by snow disposal. Freezing and thawing periods and snowmelt, often including rain-on-snow. Such events can create extreme runoff conditions. Therefore the hydrological cycle, as usually described in the literature for warm-weather conditions, becomes much more complex in cold weather.
Urbanization changes the hydrologic cycle from a natural state to an artificial state. The flow regime is changes when the natural drainage system is modified, impervious areas increase and the local microclimate change. Increase in population increase the drinking water demand and the installation of sewerage systems for both domestic and stormwater drainage may cause increase in waterborne waste.
These challengers may be worse in cold climate, having frozen ground, snow accumulated on ground etc. Therefore, cold climate and urbanization is having a great impact on the hydrology that may create extraordinary challengers on urban water management, including integration of water supply, stormwater, wastewater components of the urban water cycle.