(a) From the basin map of a given watershed with drainage area 3000 km², the length of the mainstream (L) is measured as 125 km…

(a) Snyder's coefficients Ct and Cp

Snyder's synthetic unit hydrograph (SI units): t_p = C₁·Ct·(L·Lc)^0.3 and q_p = C₂·Cp·A/t_p, where t_p is the basin lag for the standard duration t_r = t_p/5.5, and q_p is the peak for that duration.

The given hydrograph has t_R = 12 h, which is not the standard duration, so the lag is first converted:

t_pR = t_p + (t_R − t_r)/4, with t_r = t_p/5.5

34 = t_p + (12 − t_p/5.5)/4 = t_p(1 − 1/22) + 3

t_p = 31 × 22/21 = 32.48 h (so t_r = 5.9 h).

Ct = t_p/[C₁(L·Lc)^0.3]. L·Lc = 125 × 90 = 11,250 km², and 11,250^0.3 = 16.42, so

Ct = 32.48/(0.75 × 16.42) = 2.64.

The peak is converted to the standard duration using q_pR = q_p·(t_p/t_pR):

q_p = 135 × 34/32.48 = 141.3 m³/s per cm.

Cp = q_p·t_p/(C₂·A) = 141.3 × 32.48/(2.75 × 3,000) = 4,590/8,250 = 0.556.

Ct ≈ 2.64 and Cp ≈ 0.56.

(b) Municipal solid waste sanitary landfill

A sanitary landfill is an engineered site where municipal solid waste is spread, compacted in layers (cells) and covered with soil at the end of each day, so that it does not harm public health or the environment. A schematic cross-section from bottom to top shows the following components.

• Natural ground and a liner system: compacted clay (about 0.6 to 1 m) with an HDPE geomembrane and a protective geotextile, which stops leachate reaching groundwater.
• Leachate collection layer: a granular drainage blanket with perforated pipes laid to a slope, leading to a sump, pumping and a leachate treatment plant.
• Waste cells: compacted waste in lifts of about 2 to 3 m, each with a daily soil cover (about 15 cm) to limit odour, vermin, litter and fires, and an intermediate cover.
• Gas collection system: vertical wells and horizontal headers drawing methane and CO₂ to a flare or an energy plant.
• Final cover: a clay or geomembrane barrier, a drainage layer and topsoil with vegetation, which reduces rain infiltration.
• Surface drainage: diversion drains and a sedimentation pond to keep runoff away from the waste.
• Monitoring and support works: groundwater monitoring wells, gas probes, a buffer zone, fencing, a weighbridge and an access road.

After closure the site is monitored for leachate, gas, settlement and groundwater for many years. Site selection and design follow the Solid Waste Management Rules, 2016.

(c) Award of environmental clearance

There is no separate "EIA Act 2006"; the process is laid down in the EIA Notification, 2006, issued under the Environment (Protection) Act, 1986. Its stages are:

• Categorisation: listed projects are Category A (appraised by the central Expert Appraisal Committee, EAC, and cleared by MoEFCC) or Category B (appraised by the State Expert Appraisal Committee, SEAC, and cleared by the State Environment Impact Assessment Authority, SEIAA).
• Application: the proponent applies with Form 1, a pre-feasibility report and a conceptual plan, now online through the PARIVESH portal.
• Screening (Category B only): SEAC decides whether the project is B1, needing an EIA report, or B2, which does not.
• Scoping: for Category A and B1, the EAC/SEAC fixes the Terms of Reference for the EIA study.
• EIA report and EMP: the proponent, through an accredited consultant, collects baseline data, predicts impacts and prepares the EIA report and Environmental Management Plan.
• Public consultation: the State Pollution Control Board holds a public hearing (to be completed within 45 days) after local notice, and the report is revised for the concerns raised. Some projects are exempt.
• Appraisal: the EAC/SEAC examines the final report and the hearing record, normally within 60 days, and recommends clearance with conditions or rejection.
• Decision: the regulatory authority, MoEFCC or SEIAA, normally decides within 45 days of the recommendation, and grants clearance with specific conditions and a validity period or rejects it with reasons. Compliance reports then follow.