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In-depth guidance on Norwegian water and wastewater design — based on Norsk Vann, NVE, SVV.

Articles available in Norwegian

Full article text is currently in Norwegian (Bokmål), since the regulatory references (Norsk Vann VA-Miljøblad, NVE, SVV N200) are Norwegian. English abstracts are provided below — click an article to read the full Norwegian version.

Climate factor 2026 — adjusting design rainfall

How to apply the Norwegian climate factor (1.2–1.5) to design rainfall, with worked examples for stormwater pipes and detention basins. Common mistakes: applying K_f to the runoff coefficient C instead of the rainfall intensity, and forgetting K_f for detention volume calculations.

Climate6 min read15 Apr 2026Norwegian

Self-cleansing in sewers — from theory to design

Practical design of gravity sewers to avoid sediment build-up. Covers shear stress (τ ≥ 1.5 N/m²) and velocity (v ≥ 0.6 m/s) criteria, the importance of checking minimum flow scenarios, and how manholes need separate consideration.

Wastewater8 min read20 Apr 2026Norwegian

Manning's n: choosing the right value

Roughness coefficient values for Norwegian and international pipe materials. PVC, PE, concrete, ductile iron, ageing factors, and how to choose conservatively when uncertain. Tabular reference for common materials.

Hydraulics5 min read22 Apr 2026Norwegian

Detention volume — finding critical duration

Stormwater detention basin sizing using the rational method and continuous simulation. Why time of concentration is not the same as design rainfall duration, and how to find the critical duration that gives maximum storage requirement.

Stormwater6 min read25 Apr 2026Norwegian

Culvert design using FHWA HDS-5

Inlet versus outlet control culvert design following the US Federal Highway Administration HDS-5 manual. Compute headwater for both control modes and use the higher one — that mode dominates the system.

Design7 min read28 Apr 2026Norwegian

EPANET vs SWMM — riktig verktøy for riktig system

Drikkevann under trykk er ikke det samme som overvann i selvfall. Slik velger du mellom EPANET og SWMM, og hvorfor det utgjør en stor forskjell for dimensjoneringen.

Hydraulics5 min read2 May 2026Norwegian

Pumpe-dimensjonering: NPSH og driftspunkt forklart

Pumpe-Q-H-kurven krysses med systemkurven i ett driftspunkt. Slik finner du det, og hvorfor NPSH-margin er kritisk for å unngå kavitasjon.

Water supply7 min read2 May 2026Norwegian

Kombinert eller separatsystem — når velge hva?

Kombi (felles overvann + spillvann i samme rør) eller separatsystem? Klimaendringer presser mot separat, men kombi kan fortsatt være riktig i noen tilfeller.

Design6 min read2 May 2026Norwegian