How does urbanization affect hydrographs?
The rising limbs of storm hydrographs become steeper and higher in urbanizing areas. Recession limbs also decline more steeply in urban streams. The increased runoff and decreased infiltration recharge less ground water, which also results in lower baseflow after the storm runoff is over.
What are stream hydrographs?
A hydrograph is a graph of the flow in a stream over a period of time. Below is a picture of a hydrograph, with stream flow (discharge) in cubic feet per second on the y-axis and time in months on the x-axis. Peaks in the hydrograph are usually a result of precipitation events, while troughs represent drier times.
What are the two types of hydrographs?
Types of hydrographs include: Storm hydrographs. Flood hydrographs. Annual hydrographs a.k.a. regimes.
How does urbanization affect watersheds?
Urbanization has a detrimental effect on watersheds by decreasing vegetation and increasing impermeable surfaces, says new research by SRS scientists.
How does urbanization impact streamflow?
The study found urbanization does not change streamflow consistently. Low flows went up in about half the streams and went down in the other half. High flows generally increased with urbanization, with the largest increases in semi‐arid and arid areas.
How does urbanization cause flash flooding?
The changes in land use associated with urban development affect flooding in many ways. Removing vegetation and soil, grading the land surface, and constructing drainage networks increase runoff to streams from rainfall and snowmelt.
What are hydrographs used for?
In its simplest form, a hydrograph is a graphical representation of runoff rate against time (Figure 1). It shows the time distribution of runoff at the point of measurement or computation, reflecting the complex characteristics of the watershed by a single curve.
How does land use affect storm hydrographs?
The way in which the land is used will also have an influence on the hydrograph – vegetation intercepts precipitation and allows evaporation to take place directly into the atmosphere so reducing the amount of water available for overland flow while the large number of impermeable surfaces in urban areas encourages run …
Why do hydrographs differ?
Hydrographs can take different shapes dependent upon the characteristics of the drainage basin. The various flows and stores of the drainage basin are affected by these characteristics, and these in turn will affect the shape of the hydrograph and the volume of water in a river.
How does urbanization affect peak flow?
Urbanization generally results in increased magnitude and frequency of peak flows. However, baseflow effects typically are more variable, with studies showing a range of responses in urban streams [Lerner 2002, Brandes et al.
How does urbanization affect the air?
Using a cross-sectional data of 282 cities, Lin and Zhu found that the urbanization process has a significant and negative effect on air pollutant concentration, which means that cities with higher urbanization rate tend to have lower air pollutant concentration, including SO2, PM2.5 and PM10 (Lin and Zhu, 2018).
How does urbanization impact streamflow quizlet?
Urbanization increases maximum stream flow and decreases lag time.