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222-acre lake near West Lothian. The lake tops out around 30 ft. The depth chart comes from published agency bathymetric survey data, so the contours are survey-derived rather than computer-modeled. The depth data here comes from Murray & Pullar's Scottish loch survey of 1903, digitized from the bathymetric atlas published in 1910. What the data behind the map says about each species, season by season:
Harperigg Reservoir maps at 221 acres behind 3.5 miles of shoreline. A middling shoreline index (1.7) gives it some bays to work without being a maze. Roughly 69% of the water is 15 ft or less, the band where the food chain lives. The basin spans about 1.2 mi end to end and 0.6 mi across at its widest. West Lothian claims this one. Its nearest charted neighbour, Threipmuir Reservoir, is 5 mi to the east.
Start shallow in spring: brown trout sit in 3 to 25 ft that time of year. Summer pushes them deeper, 9 to 30 ft, and winter fish settle into 4 to 30 ft. The spot to know is Deep basin, a deep basin in about 30 ft of water that rates prime for brown trout in summer. Warm-month bites cluster around after dark and early morning. Throw a spoon at the thermocline or a deep stickbait (night) until the fish tell you otherwise.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 25 ft | dawn & dusk | Main-lake point (12 ft) | Stickbait off planer boards (shallow), Small spoon along mud lines |
| Summer | 9 to 30 ft chart-limited; documented 25 to 60 ft | night & dawn | Deep basin (30 ft) | Spoon at the thermocline, Deep stickbait (night) |
| Fall | 5 to 30 ft | dusk & dawn | Main-lake point (12 ft) | Jerkbait over gravel, Casting spoon |
| Winter | 4 to 30 ft chart-limited; documented 5 to 35 ft | dawn | Deep basin (30 ft) | Jigging spoon, Small stickbait (slow) |
When the water first warms, european perch slide up into 3 to 12 ft. By summer they slide out to 8 to 28 ft, and by winter most fish are in 9 to 30 ft. If you only fish one area, make it Deep basin: a deep basin around 30 ft that scores prime in fall. In summer the feeding windows fall in early morning. Keep a drop-shot micro plastics or a small crankbait (perch pattern) rigged through the warm months.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (2 ft) | Small jig + curly tail, Inline spinner #1-2 |
| Summer | 8 to 28 ft | dawn | Deep basin (30 ft) | Drop-shot micro plastics, Small crankbait (perch pattern) |
| Fall | 9 to 30 ft chart-limited; documented 10 to 33 ft | midday | Deep basin (30 ft) | Jigging spoon (small), Drop-shot on deep flats |
| Winter | 9 to 30 ft chart-limited; documented 12 to 33 ft | midday & dawn | Deep basin (30 ft) | Tungsten jig + maggots, Small balance jig |
Spring northern pike on Harperigg Reservoir hold shallow, usually 2 to 8 ft. By summer they slide out to 8 to 20 ft, and by winter most fish are in 5 to 15 ft. The chart's best answer is Shallow bay flat — weed flat, 2 ft, prime for spring. Prime time lands in early morning and the evening. The summer box starts with a bucktail or a weedless spoon over cabbage.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (2 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Main-lake point (12 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Main-lake point (12 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Main-lake point (12 ft) | Tip-ups, Large jigging spoon |
Spring puts arctic char in skinny water — 4 to 15 ft is the zone. Warm water sends them out to 9 to 30 ft; cold water stacks them in 8 to 30 ft. Deep basin is the standout, a deep basin at roughly 30 ft, rated prime for summer arctic char. Plan around early morning in the warm months. A jigging spoon vertical or a tube jig (smelt) covers the summer program.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | midday & dawn | Break off the point (2 ft) | Small casting spoon (silver/orange), Jerkbait (small) |
| Summer | 9 to 30 ft chart-limited; documented 20 to 60 ft | dawn | Deep basin (30 ft) | Jigging spoon vertical, Tube jig (smelt) |
| Fall | 8 to 30 ft | midday & dusk | Break off the point (2 ft) | Casting spoon (orange/gold), Beadhead streamer |
| Winter | 8 to 30 ft chart-limited; documented 10 to 40 ft | midday & dawn | Deep basin (30 ft) | Jigging spoon (glow/silver), Tungsten jig + plastic |
6 pieces of structure are mapped here — Deep basin, around 30 ft, is the deepest of them.
Harperigg Reservoir is about 30 ft (9 m) deep at its deepest point. The depth data here comes from Murray & Pullar's Scottish loch survey of 1903, digitized from the bathymetric atlas published in 1910.
Anglers target brown trout, european perch, northern pike, arctic char on Harperigg Reservoir. This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.
Deep basin is the top-rated area: a deep basin in about 30 ft of water that rates prime for european perch in fall. Open the map above to see every rated spot for each species and season.
For brown trout, the summer bite is best in after dark and early morning. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Threipmuir Reservoir 5 mi · Harlaw Reservoir 6 mi · Slipperfield Loch or Dalmahoy Loch 7 mi · Linlithgow Loch 12 mi · Portmore Loch 12 mi · Edgelaw Reservoir 13 mi · Gladhouse Reservoir 13 mi · Rosebery Reservoir 13 mi · Duddingston Loch 14 mi · Loch Fitty 19 mi · Kinghorn Loch 19 mi · Moor Loch 19 mi
See how Harperigg Reservoir stacks up: best northern pike lakes in United Kingdom · best european perch lakes in United Kingdom · best brown trout lakes in United Kingdom · best arctic char lakes in United Kingdom
Browse all United Kingdom fishing maps. See every water on DepthScout. Bathymetry: published agency survey data. How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.