The Swale Desk
This desk watches one corner of the world: the shallow channels, ridges, and pipes that keep runoff out of basements and off pavement. Every page here starts from three numbers you can measure in an afternoon — grade, percolation rate, and catchment area. Any drainage decision made without them is a guess wearing a plan.
Close this tab if your yard already drains: this desk exists for the three numbers you do not have yet.
The ledger
Entries as they were written or re-checked. The ledger is the desk's spine: nothing on this site claims to be fresher than its entry.
| Date | Condition or question | Points to | Number |
|---|---|---|---|
| 2026-09-10 | Wet-season walk: measure before you buy anything | Measure yard grade | 3 numbers |
| 2026-09-05 | Where pipes must go below frost, and where they never do | Frost line note | 0–6 ft |
| 2026-09-02 | Why 72 hours of standing water is the rule, and where it comes from | 72-hour rule | 72 h |
| 2026-09-01 | Grass or rock in the channel — the trade-offs nobody states plainly | Grass or rock note | 2 options |
| 2026-08-25 | Carry a downspout to the swale, or bury it: the arithmetic | Downspout math | 1% min |
| 2026-08-18 | Perforated pipe: holes up or holes down, and who disagrees | Holes up or down | 2 camps |
| 2026-07-30 | What “1 inch per hour” means in a perk test — and the unit trap | Inch per hour note | 1 in/hr |
| 2026-07-15 | Sock-wrapped perforated pipe: what vendor pages omit | Sock marketing note | 0 tests |
Objects
Things with boundaries. Each object page defines one thing, lists its near kin, and shows where it stops working. No object page sells a fix; it sets the rules a fix must obey.
- Swale — the planted channel. Boundary vs ditch, French drain, rain garden.
- Berm — the ridge that makes a swale hold water.
- French drain — the pipe system, and when it is the wrong fix.
- Check dam — small rock or wood barriers inside a channel.
- Grade — slope as percent, and how to read a level.
- Percolation rate — the number that chooses swale or drain.
- Catchment — roof and yard square footage that feeds the wet spot.
- Catch basin — inlet, sump, and the trap of a buried pond.
- Dry well — underground storage that only works on a passing perk rate.
- Riprap — stone armor for fast water, and its sizing rules.
Jobs
Things you can finish today. Each job page runs on a real time box, lists tools, and marks the points where people stop.
- Run a percolation test with a bucket — one afternoon, mostly waiting.
- Measure yard grade with a line level — 30 minutes.
- Calculate roof and yard catchment — 30 minutes of arithmetic.
- Size a swale from three numbers — one hour at a table.
- Build check dams in a swale — half a day, rock and stakes.
- Plant a swale that does not wash out — seasonal, half a day.
- Read your city's drainage code — one hour, no digging.
- Diagnose standing water — the three-number check, one hour.
Notes
Dated judgments, disputes, and arithmetic. Notes can go stale, and say so in their header when they do.
- The 72-hour standing-water rule (2 Sep 2026)
- Perforated pipe: holes up or down (18 Aug 2026)
- Grass-lined or rock-lined swale (1 Sep 2026)
- What 1 inch per hour actually means (30 Jul 2026)
- Frost line and why the north digs deeper (5 Sep 2026)
- Carry a downspout or bury it: the arithmetic (25 Aug 2026)
- Sock-wrapped pipe: what vendor pages omit (15 Jul 2026)
Desk files
How the desk works, what it refuses, and who answers when a figure is wrong: method, refuse list, the desk, contact, privacy.
Sources
- Minnesota Stormwater Manual — Design criteria for wet swale (wetland channel) — supports the swale cross-section and check-dam spacing drawn above.
- US EPA — NPDES stormwater program — supports what the federal stormwater program covers.
- USGS Water Science School — Runoff: surface and overland water runoff — supports how runoff gets from a roof and yard to the swale.