16-Civ-A3 Elementary Environmental Engineering · December 2018
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Paper format. National Exams, December 2018 — 16-Civ-A3 Elementary Environmental Engineering. Three hours; closed book with one candidate-prepared 8½ × 11 double-sided aid sheet; approved Casio or Sharp calculator only. Seven problems are printed, each worth 20 marks, and any five constitute a complete paper (maximum 100 marks). All seven are solved here, because the set is intended as a study resource rather than an exam script. Section marks are shown in brackets at the left margin of each question and are reproduced from the final-page Marking Scheme.
Reference texts.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
The aquifer faces contamination from mine drainage (acid rock drainage, dissolved metals) and over-extraction. Strategy 1 — Source-water protection zoning and land-use control (non-technical/technical): delineate wellhead and aquifer capture zones and impose land-use restrictions and permitting within them, so that the mine’s tailings, waste rock and process ponds are sited and lined to keep contaminants out of the recharge area — the cheapest protection is preventing the release. Strategy 2 — Monitoring network and early-warning (technical): install a groundwater monitoring-well network between the mine and the supply wells to track water levels and indicator parameters (pH, sulfate, metals, conductivity); trend analysis separates natural variability from a genuine impact and triggers response before the supply is affected. Strategy 3 — Engineered containment and remediation, plus demand management (technical): require the mine to use lined impoundments, seepage collection and treatment (e.g., neutralisation of acid drainage), and cap sustainable extraction to the recharge rate so the aquifer is not mined; contingency includes pump-and-treat or a permeable reactive barrier if a plume develops. Short-term protection comes from monitoring and containment; long-term protection comes from zoning, sustainable-yield management and enforceable agreements with the operator, consistent with Canadian source-water-protection practice.
As watershed manager of a lake serving both drinking-water supply and recreation, an integrated (IWRM) approach balances multiple uses. Strategy 1 — Watershed nutrient and runoff control (technical): the chief threat to a recreational drinking-water lake is eutrophication, so control phosphorus at source — upgrade wastewater plants to advanced nutrient removal, require agricultural best-management practices and riparian buffer strips, and manage urban stormwater with low-impact development to cut nutrient and sediment loading. Strategy 2 — Integrated monitoring and adaptive management (technical/non-technical): a watershed-wide monitoring programme (tributary loads, in-lake nutrients, algae, pathogens, recreational water quality) feeds a mass-balance/water-quality model that sets a total maximum load and lets management adapt as conditions change. Strategy 3 — Governance, stakeholder engagement and regulation (non-technical): establish a watershed authority coordinating municipalities, agriculture, industry and the public around a shared plan, with land-use planning, source-water protection bylaws, and public education to align the many users. Long-term sustainability depends on this institutional coordination as much as on the engineering, since the lake integrates every activity in its watershed. In the Canadian context this aligns with provincial source-water protection and IWRM frameworks and CCME water-quality guidelines.
