The DIKSHA Catch the Rain professional development module, organized under the NISHTHA program by the Ministry of Education and National Water Mission (Ministry of Jal Shakti), provides educators and administrators with essential principles of hydrology, surface runoff management, and institutional water budgeting.

This technical guide delivers the complete verified answer key for Module 3 Formative Assessment 02, accompanied by hydrological formulas, engineering concepts, and institutional implementation guidelines.

Parameter	Details
Course Name	NISHTHA / DIKSHA Catch the Rain Training
Module	Module 3: Hydrological Concepts & Water Conservation Metrics
Assessment Type	Formative Assessment 02 (Matching Terms)
Passing Score	Minimum 70% required for course certification
Governing Bodies	Ministry of Education, Ministry of Jal Shakti, NCERT

Formative Assessment 02: Verified Matching Matrix

Quick Reference Table

Column A (Key Term)	Column B (Matching Term)	Core Hydrological Focus
1. Harvesting	Rainwater	Collection and storage of atmospheric precipitation before runoff
2. Runoff	Coefficient	Ratio of surface runoff volume to total rainfall volume
3. Leakage	Water wastage	Unaccounted physical loss in supply and distribution pipes
4. Annual	Rainfall	Total cumulative precipitation depth measured over 365 days
5. Footprint	Consumption	Total direct and indirect freshwater volume utilized by an entity

Technical Analysis of Assessment Concepts

1. Harvesting → Rainwater

Rainwater harvesting (RWH) is the collection, conveyance, and storage of runoff generated by natural rainfall for immediate domestic, agricultural, or environmental recharge purposes.

• Primary Catchments: Rooftops, paved surfaces, open grounds, and agricultural watersheds.
• Storage vs. Recharge: Depending on regional geology, collected water is either diverted directly into closed storage tanks or directed into artificial recharge structures (recharge pits, trenches, or injection wells) to replenish unconfined aquifers.

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2. Runoff → Coefficient

The Runoff Coefficient (C) is a dimensionless parameter used in hydrological engineering to represent the fraction of total rainfall that converts into surface runoff rather than infiltrating into the soil or evaporating.

The Rational Method Formula

Peak surface runoff rate (Q) is calculated using the standard Rational Formula:

Q=C⋅I⋅A

Where:

• Q = Peak runoff rate (m3/s)
• C = Dimensionless Runoff Coefficient
• I = Rainfall intensity (mm/hr)
• A = Catchment surface area (m2)

Representative Runoff Coefficients (C)

• Concrete / Roof Surfaces: 0.80−0.95 (High yield, minimal infiltration)
• Paved Asphalt Roads: 0.70−0.85
• Parks and Lawn Soil: 0.10−0.25 (High infiltration capacity)

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3. Leakage → Water Wastage

In municipal and institutional water distribution systems, leakage represents non-revenue water (NRW) caused by pipe fractures, faulty joint seals, or excessive system pressure.

• Impact on Institutions: Unchecked leaks in school drinking water lines and sanitation blocks lead to continuous ground saturation, structural foundation damage, and severe financial waste.
• Mitigation Strategy: Routine acoustic leak detection, installation of pressure-reducing valves (PRVs), and preventative pipe replacement.

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4. Annual → Rainfall

Annual Rainfall (P) measures the total depth of precipitation recorded at a specific meteorological station over a calendar year, typically expressed in millimeters (mm).

Sizing Rainwater Storage Structures

The theoretical annual volume (V) of collectible water from a rooftop catchment is derived as:

V=A⋅P⋅C⋅η

Where:

• V = Total annual harvestable water volume (Liters)
• A = Catchment area (m2)
• P = Mean annual rainfall (mm)
• C = Surface runoff coefficient
• η = First-flush and filtration efficiency factor (typically 0.80−0.90)

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5. Footprint → Consumption

A Water Footprint assesses the total volume of freshwater consumed, degraded, or evaporated directly and indirectly by an individual, institution, or manufacturing process.

Total Water Footprint Equation

The comprehensive water footprint (WFtotal​) consists of three distinct hydrological components:

WFtotal​=WFblue​+WFgreen​+WFgrey​

• Blue Water Footprint (WFblue​): Volume of surface water and groundwater consumed.
• Green Water Footprint (WFgreen​): Volume of rainwater stored in soil moisture used by plants/crops.
• Grey Water Footprint (WFgrey​): Volume of freshwater required to assimilate pollutants to meet water quality standards.

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Step-by-Step Guide to Complete Module 3 on DIKSHA

1. Access Portal: Log in to the official DIKSHA App or web portal using your state-registered teacher account.
2. Open Course: Go to My Courses → CPD Catch the Rain → Module 3.
3. Launch Assessment: Select Formative Assessment 02 from the course outline.
4. Match Terms: Pair the terms in Column A with Column B using the verified key provided in this guide.
5. Submit & Review: Click Submit to record your responses and ensure progress syncs to your portal dashboard.

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Frequently Asked Questions (FAQs)

What is the primary factor affecting the runoff coefficient of a catchment area?

The surface material’s permeability is the primary factor. Impervious surfaces like concrete roofs have high runoff coefficients (approaching 1.0), while vegetated soil has a low runoff coefficient due to infiltration.

What standard governs rooftop rainwater harvesting design in Indian institutions?

The Bureau of Indian Standards code IS 15797:2008 provides regulatory guidelines for designing, installing, and maintaining roof top rainwater harvesting systems.

How does calculating a school’s water footprint help in water conservation?

Calculating the water footprint identifies operational areas with excessive consumption or waste, allowing administrators to implement targeted conservation measures such as low-flow fixtures and greywater recycling.