Hydrology

Step 1: Understanding the question.
The question asks about a geological formation that neither contains nor transmits water. This type of formation is important in hydrogeology.
Step 2: Analyzing the options.
(A) aquiclude: This is a correct option, but it refers to a formation that significantly limits water movement. However, the term "aquifuge" is more specific to a formation that is completely impermeable and doesn't transmit any water.
(B) aquitard: An aquitard is a formation that does transmit some water, though at a much slower rate than an aquifer.
(C) aquifer: This is incorrect, as an aquifer is a formation that stores and transmits significant amounts of water.
(D) aquifuge: Correct — An aquifuge is a geological formation that is completely impermeable and does not allow water to pass through, making it the correct choice for a formation that neither contains nor transmits water.
Step 3: Conclusion.
The correct answer is (D) aquifuge, as it specifically refers to a formation that is completely impermeable and does not transmit or contain water.

Step 1: Understanding the question.
Check dams are smaller structures built in association with main dams to control water flow and reduce the siltation in reservoirs. The correct location for their construction is critical to their function.
Step 2: Analyzing the options.
(A) upstream of the main dam to check the siltation of the reservoir: Correct — Check dams are often constructed upstream to control the flow and reduce the amount of silt entering the reservoir.
(B) downstream of the main dam to check the siltation of the reservoir: Incorrect — Siltation occurs before the water reaches the main reservoir, so a check dam downstream would not be effective in reducing siltation.
(C) upstream of the main dam to check the seepage from the reservoir: Incorrect — Check dams upstream are typically used to prevent siltation, not to manage seepage.
(D) downstream of the main dam to check the seepage from the reservoir: Incorrect — Check dams help with controlling water flow and siltation, not seepage.
Step 3: Conclusion.
The correct answer is (A) upstream of the main dam to check the siltation of the reservoir, as it is the most effective placement for reducing siltation.

Step 1: Understanding drainage density.
Drainage density is defined as the total length of all streams (in km) in a drainage basin divided by the area of the basin (in km ). The formula for drainage density is: Step 2: Calculating the total length of streams.
The total length of streams is the sum of the lengths of the 1st, 2nd, 3rd, and 4th order drainages: Step 3: Calculating the drainage density.
The area of the basin is given as 40 sq. km. Therefore, the drainage density is: Step 4: Conclusion.
The drainage density of the basin is 0.75 km .

Step 1: Understanding the question.
The drainage density is calculated as the total length of all drainage divided by the area of the basin.
Step 2: Analyzing the solution.
The total length of drainage is the sum of the lengths of the drainage for each order: Next, calculate the drainage density: Step 3: Conclusion.
The correct answer is 1.4 km/km².

Step 1: Understanding the question.
Check dams are smaller structures built in association with main dams to control water flow and reduce the siltation in reservoirs. The correct location for their construction is critical to their function.
Step 2: Analyzing the options.
(A) upstream of the main dam to check the siltation of the reservoir: Correct — Check dams are often constructed upstream to control the flow and reduce the amount of silt entering the reservoir.
(B) downstream of the main dam to check the siltation of the reservoir: Incorrect — Siltation occurs before the water reaches the main reservoir, so a check dam downstream would not be effective in reducing siltation.
(C) upstream of the main dam to check the seepage from the reservoir: Incorrect — Check dams upstream are typically used to prevent siltation, not to manage seepage.
(D) downstream of the main dam to check the seepage from the reservoir: Incorrect — Check dams help with controlling water flow and siltation, not seepage.
Step 3: Conclusion.
The correct answer is (A) upstream of the main dam to check the siltation of the reservoir, as it is the most effective placement for reducing siltation.

Step 1: Understanding the question.
The question asks about a geological formation that neither contains nor transmits water. This type of formation is important in hydrogeology.
Step 2: Analyzing the options.
(A) aquiclude: Correct — An aquiclude is a geological formation that does not contain or transmit significant amounts of water, often acting as a barrier to groundwater movement.
(B) aquitard: An aquitard is a layer that can transmit some water but at a slower rate than an aquifer. It still allows water to pass through, though not easily.
(C) aquifer: An aquifer is a formation that can store and transmit significant amounts of water, making it the opposite of an aquiclude.
(D) aquifuge: An aquifuge is a layer that is completely impermeable, which could theoretically be seen as a more restrictive type of aquiclude, but the term aquiclude is more commonly used.
Step 3: Conclusion.
The correct answer is (A) aquiclude, as it refers to a geological formation that neither contains nor transmits water.

Step 1: Use Darcy's law.
Darcy's law for groundwater flow is given by the equation: Where: - (flow rate) - (cross-sectional area) - (hydraulic gradient) We need to find , the hydraulic conductivity. Rearranging the equation: Substituting the values: Thus, the hydraulic conductivity of the aquifer is 1 m/sec.

Step 1: Understanding the statements.
- (A) Weathered granite generally has higher porosity than crystalline granite, making this statement incorrect.
- (B) Coarse sands do indeed have high porosity and high permeability because they allow water to flow through more easily.
- (C) Clays have high porosity, but their permeability is low due to the fine particles, making this statement incorrect.
- (D) Groundwater table fluctuates with water recharge, so this statement is incorrect.

Step 2: Conclusion.
The correct answer is (B) Coarse sands have high porosity and high permeability.

Step 1: Understanding groundwater hardness.
Groundwater hardness is determined by the concentration of calcium and magnesium ions dissolved in the water. These ions are the primary contributors to the hardness of water.

Step 2: Analyzing the options.
(A) Mohs' scale of hardness: This scale is used to measure the hardness of minerals, not groundwater.
(B) concentrations of calcium and magnesium: Correct — The hardness of groundwater is typically due to the concentration of these two minerals.
(C) Bernoulli equation: The Bernoulli equation is used to describe the flow of fluids and is not related to water hardness.
(D) Darcy's law: Darcy's law is used to describe the flow of water through porous media, not the hardness of water.

Step 3: Conclusion.
The correct answer is (B) concentrations of calcium and magnesium, as they directly contribute to the hardness of groundwater.