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322-acre lake near North Dakota. North Dakota Game & Fish survey water. The lake tops out around 45 ft. The depth chart is built from real state fisheries GPS surveys, so the humps, channels and drop-offs you see are measured, not guessed. Every species below gets its seasonal read from the same numbers driving the chart.
Traced from the shoreline, Riverdale Spillway Lake runs 322 acres with 5.8 miles of edge. The 2.3 development index tells the story — a convoluted bank whose fishable edge far outruns the acreage. Littoral water — the productive band under ~15 ft — makes up 88% of this chart. The basin spans about 2.8 mi end to end and 0.2 mi across at its widest. You'll find it in McLean County. For a second option, Harmony Lake lies 13 mi southwest.
Spring puts largemouth bass in skinny water — 2 to 10 ft is the zone. Warm water sends them out to 8 to 20 ft; cold water stacks them in 15 to 35 ft. Shallow bay flat is the standout, a weed flat at roughly 7 ft, rated prime for spring largemouth bass. Plan around early morning and the evening in the warm months. A texas-rigged 10" worm or a deep-diving crankbait covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (7 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (7 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (7 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (6 ft) | Blade bait, Jigging spoon |
Start shallow in spring: bluegill sit in 1 to 6 ft that time of year. Warm water sends them out to 4 to 15 ft; cold water stacks them in 10 to 25 ft. Top water on the chart: Shallow bay flat, a weed flat in the 7 ft range, prime in summer. Fish it in early morning and the evening and you'll meet the bite. Throw a small sponge spider (fly) or a micro tube jig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (7 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (7 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (7 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Back-bay flat (24 ft) | Tungsten ice jig + plastic, Tiny spoon |
Riverdale Spillway Lake carries 6 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 44 ft down.
Season dates, license requirements, and size and bag limits for North Dakota waters are set by the North Dakota Game and Fish — and special regulations can apply to Riverdale Spillway Lake specifically, so confirm the current rules before you fish.
Check the official North Dakota fishing regulations →
Riverdale Spillway Lake is about 45 ft (14 m) deep at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.
Anglers target largemouth bass, bluegill on Riverdale Spillway Lake.
Shallow bay flat is the top-rated area: a weed flat in about 7 ft of water that rates prime for largemouth bass in spring. Scroll up to the map for the complete spot list by species and season.
For largemouth bass, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on Riverdale Spillway Lake is regulated by the North Dakota Game and Fish. Check the official North Dakota regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Harmony Lake 13 mi · Lake Audubon 14 mi · Coal Lake 16 mi · Lake Brekken 25 mi · Lake Holmes 26 mi · Missouri River 27 mi · Scooby Lake 28 mi · Nelson Lake 28 mi · Cottonwood Lake 29 mi · West Park Lake 31 mi · South Carlson Lake 31 mi · Long Lake 31 mi
See how Riverdale Spillway Lake stacks up: best largemouth bass lakes in North Dakota · best bluegill lakes in North Dakota
More water nearby: McLean County fishing maps (12 charts). Browse all North Dakota fishing maps or see every water on DepthScout. Bathymetry credit: state fisheries survey programs. 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.