Column-I Column-II 1) Neutron Probe P) Open channel flow 2) Pressure Plate Apparatus Q) Deep percolation 3) Tipping Bucket R) Aquifer parameters 4) Current Meter S) Soil moisture 5) Pumping Test T) Rainfall intensity 6) Lysimeter U) Soil-moisture characteristic curve
Matching Hydrology Instruments and Applications
This question requires matching instruments from Column-I with their primary applications or measurement types in Column-II.
Column-I to Column-II Matching
- 1) Neutron Probe is used to measure S) Soil moisture content in the field. It works by detecting the moderation of fast neutrons by hydrogen atoms in water.
- 2) Pressure Plate Apparatus is a device used in soil science to determine the soil-moisture characteristic curve, which relates soil water content to soil water potential. This corresponds to U) Soil-moisture characteristic curve.
- 3) Tipping Bucket is a common component of a rain gauge used to measure T) Rainfall intensity. Each tip of the bucket represents a specific, known amount of rainfall.
- 4) Current Meter is an instrument used to measure water velocity, typically in rivers or open channels. This is essential for calculating flow rates, hence relating to P) Open channel flow.
- 5) Pumping Test is a field method used to determine the hydraulic properties of aquifers, such as transmissivity and storativity. This matches with R) Aquifer parameters.
- 6) Lysimeter is used to measure water balance components, including evapotranspiration and deep percolation. Therefore, it relates to Q) Deep percolation.
Final Combinations
Based on the analysis, the correct matches are:
- Neutron Probe (1) – Soil moisture (S)
- Pressure Plate Apparatus (2) – Soil-moisture characteristic curve (U)
- Tipping Bucket (3) – Rainfall intensity (T)
- Current Meter (4) – Open channel flow (P)
- Pumping Test (5) – Aquifer parameters (R)
- Lysimeter (6) – Deep percolation (Q)
This corresponds to the combination 1-S, 2-U, 3-T, 4-P, 5-R, 6-Q.
Important Questions from Soil Moisture Measurement
- An undisturbed soil sample is collected from a field with core cylinder having an internal diameter of $60\text{ mm}$ and length of $100\text{ mm}$. The weights of moist soil and oven dried soil are $0.48\text{ kg}$ and $0.44\text{ kg}$, respectively. Assuming density of water as $1000\text{ kg.m}^{-3}$, the water depth (in metres per metre depth of soil) is ________
(Rounded off to two decimal places) - In-situ volumetric soil moisture content measuring method(s) is/are:
- The elevations of pressure gauge and porous cup of the tensiometer installed in unsaturated zone are 145.8 m and 144.2 m, respectively. Pressure measured at the gauge is $-19.62\times10^3$ $N$ $m^{-2}$. The specific weight of water is 9810 $N$ $m^{-3}$. The estimated pressure at the porous cup is ________ $N$ $m^{-2}$.
- Tensiometer installed in the soil measures
Undisturbed soil sample is collected from a field when the soil moisture is at field capacity. The inside diameter of the core sampler is 7.5 cm with a height of 15 cm. Weight of the core sampling cylinder with moist soil is 2.81 kg and that with oven dry soil is 2.61 kg. The weight of the core sampling cylinder is 1.56 kg. Assuming $\pi = 3.14$, the water depth in centimeter per meter depth of soil (rounded off to two decimal places) is__________.
