The document discusses various methods related to hydrology, including the Thiessen polygons method for precipitation data interpolation, the Snyder and SCS methods for developing unit hydrographs for ungagged basins, and the significance of environmental factors in evapotranspiration. It also covers storm characteristics, measurement methods for precipitation, and parameters crucial for design storms. Additionally, it emphasizes the use of NEXRAD technology for spatial precipitation measurement and details tools for determining river flow discharge.

1. The Thiessen polygons method is a common method used to interpolate precipitation data over
time. Two common methods to develop a unit hydrograph for ungagged basins are the Snyder
and the SCS. The temperature is the only environmental factor affecting potential
evapotranspiration. Both the phi Index and the Green-Ampt are common methods in engineering
to estimate water infiltration. Early this week the Mason Campus was closed due the effects of
Winter Storm Titan. This storm is a clear example of a convective precipitation event. The Time
of rise (Tr) as defined when using the unit hydrograph method represents the total duration of the
runoff. Base flow in a stream results from flows from the groundwater into the stream.
Hydraulics is the field that studies the occurrence, distribution, movement and properties of
water on earth. Rain gages are instruments used to measure precipitation at a point scale. On the
other hand radars such as the NEXRAD can be used to measure precipitation over a larger spatial
scale. Important parameters for design storms are volume, duration, frequency and intensity
The rational method is designed to calculate runoff for very large watersheds (e.g.: Mississippi
river watershed) given the runoff coefficient, rainfall intensity and watershed areas. River flow
is usually determined by measuring water levels and applying a rating curse to convert water
levels to discharge.
Solution
1. True - theissen polygon method is the most common method used to calculate precipitation
data over time and when there is more than one measurement.in this the area is divided into no.of
polygons eachone around a measurement point,and then take a weighted avg of polygon based
on size of each polygon.
2. True - these both snyder and SCS are the two methods along with commons dimensionless
method.in these three methods snyder is the mostly used method to develop unit hydrograph for
ungagged basins.
3. False - the evapotransparation process is not only effected by temperature but also due to soil
characteristics,physical attributes of vegitation,water availaability etc.
4. False - green and ampt method is used to estimate water infiltration along with some other
methods like richards equation,hoston equation,darchys law etc.and phi-index method is used to
compute excess rainfall hetrograph using total rainfall hetrograph using constant phi.
5.True - this strom is a convective precipitation as these type of rainfall mostly occurs in the
form of snow or freezing liquids
6. False - the time of rise is defined as the time passt a specified point in rising limb.
7. True - the portion of stream flow that is not runoff and results from seepage of water from the
ground into a channel slowly over time.

2. 8. False - hydraulics is a science and technology concerned with the conveyance of liquids
through pipes and channels, especially as a source of mechanical force.
9. True - NEXRAD is a network of 160 high-resolution S-band Doppler weather radars operated
by the National Weather Service (NWS).NEXRAD detects precipitation and atmospheric
movement or wind. It returns datawhich when processed can be displayed in a spatial data .
10. True - the main important parameters to design strom are intensity,duration,volume and
frequency.
11. True - rational method is useful for calculating with the followin parameters Q=(CIA)/Z
Where C= runoff coefficient I= Intensity A= area Z=conversion factor.
12. True - float method is used to determine the discharge of river flow.