Physical monitoring
Physical monitoring involves recording all of the physical parameters of the stream. This means recording the characteristics of the stream itself and the area surrounding it.
Common physical attributes to measure are: surrounding cover, type of stream bottom, stream width, depth, velocity, and discharge. the cover surrounding a stream can greatly influence its characteristics. It is important to note if any of the stream is covered by trees or particularly in the sunlight. This can affect the temperature of the water and the organisms found in it. The type of stream bottom can also determine what kinds of macro invertebrates that are likely to be present.
Physical monitoring can be divided into three very important sections of testing:
These parameters, used in conjunction with other monitoring techniques, are extremely useful in diagnosing and caring for the stream or water way.
Weirs
A weir is an overflow structure that is built in-stream, perpendicular to the
direction of flow, and measures the water's flow rate. A weir will impound
water behind it, acting like a small dam, so site locations must be evaluated
before construction. Many weirs are situated on smaller streams in areas
where current meter measurements are not applicable. This type of
structure is frequently utilized to establish stream flow over long periods of
time. Flow measured over an extended period of time helps to establish a
rating curve, which will allow flow to be predicted at that location. A
weir can be constructed of any type of sturdy material, such as wood, metal or
concrete.
The type and size of weir chosen for your site will depend on the flow
characteristics of the stream. There are two commonly used types of weirs,
V-notch and rectangular. A notch weir is designed to measure small flows
and a rectangular weir to measure larger flows.