Abstract:

This paper is aimed at to study and establish the relationship between the run-off or discharge of stream and rainfall or precipitation in a particular watershed.
And hence, the paper is aimed to investigate changes in stream flow patterns due to change in precipitation in different months of the year in a particular watershed.

Also the paper is aimed at to study the impact in yield of crop due to change in precipitation and hence discharge of stream in different month of the year in a particular watershed.
Ideally, it is seen that due to decrease in precipitation and hence discharge of stream, the productivity of crop is decreases due to not meet the sufficient demand of water required by the crop.

The precipitation is the general terms to be adopted for all falling things from the atmosphere to the earth that ultimately contributes to the water on the earth.
Not all rain water fall in a particular watershed are contributed to direct run off to the stream, since some of the water are evaporated, transmitted or infiltrated in to the ground.

Also, due to natural phenomenon, the rainfall varying throughout the year in any watershed and hence the runoff is also varying.
In a particular watershed, rainfall is not only varying in throughout in one year (i.e. from January to December) but also varying from year to year due to artificial cause i.e. cutting of tree for other constructional or development activities.

The effect of which the direct contribution of runoff to the stream or any natural water bodies is also varies as per varying of rainfall.
The positive and negative effect of varying rainfall and hence of direct runoff are also seen in terms of productivity of crop in irrigation land in nearby of stream or in a watershed.

The data required for writing of this paper rely on secondary sources, as at least one year time is required for collecting our own data what we called as primary data.
The most primary data or secondary data shall be gauging the run-off of stream in different months of year and measuring the rainfall through-out the year.

So, the secondary data should be analyzed to arrive at some conclusion i.e. the establishing the relationship between precipitation/rainfall and runoff/discharge of stream and productivity of crop in a particular water shed.
One of the case study concluded that there is a direct correlation exists between runoff and precipitation. i.e. the relation shall be linear mainly in the rainy season.

In the month of rainy season when the rainfall is heavy, the runoff is also heavy or more but in the month of summer season, there is no any rainfall still there is a runoff.
That means if there is no rainfall, then earlier month precipitation that infiltrate in to the ground is also contributing to run-off.
Even if the rainfall is zero in any typical month, the runoff of the stream is there and is called dry whether flow.

Again, if the rainfall is more, the discharge of the stream is more and hence the productivity of crop in a particular watershed is also more.

Introduction:

In general watershed or catchment area or drainage areas are interchangeably terms used time to time while doing hydrological analysis.
Watershed is the area over which rain water falls. Some of the water is evaporated, transmitted and infiltrate and remaining water is drained out to the common outlets.
The common outlet may be any water bodies; it may be small stream which may be perennial or not perennial, lakes, river bodies, and ocean.

In actually, small stream contributes the water flow to the river through the catchment areas which drained out water to the ocean. And ocean is the large outlet where all drain out water is collected.
Further ocean is the cause of natural hydrological cycle. In general for the stream, the catchment area is small while for the river flow, the discharge is more which is due to having the larger catchment area.
The figure shows a watershed as an representation.

A small watershed in Wyoming.

Smaller watersheds, outlined in white in this photograph are nested within the larger watershed outlined in yellow. Streams are shown in blue.

Knowing the importance of catchment areas, discharge of stream, rainfall/precipitation in the hydrological analysis which in turn lays importance in the design of any water

This problem asks you to model a stream as a 1-D plug-flow reactor...