Spring in Minnesota is a lovely time of year marked by the much anticipated sprouting of tulips, daffodils and … orange construction zone cones on roadways.

The long-awaited departure of frost from the ground in this drawn-out start to spring means more than a dozen county highway projects soon will be beginning in earnest, said Cory Slagle, engineering and construction manager with the Washington County's Public Works Department. A major interchange and intersection improvement project at Hwy. 36 and Hilton Trail in Pine Springs — a joint effort of the state and county — has already started, but other work will begin soon, he said. As usual, drivers should be alert for detours and give workers plenty of space when passing through construction zones.

The cost for Washington County projects will be about $30 million this year, aided by federal funding. The county's two largest projects this season are the reconstruction of County Road 19 (Woodbury Drive) from Eagle Valley Road to just south of Bailey Road and, farther south, a major realignment of where County Road 19 intersects with County Roads 20 (Military Road) and 22 (70th Street S.) just 800 feet apart near the Cedarhurst Mansion.

Here is a listing of county road projects:

• County Road 4A (170th Street N.), Hugo: Full-depth reclamation from the county line east to Hwy. 61. Full-depth reclamation saves money by using the existing pavement as a base for the new roadway. The existing pavement is ground up, graded and compacted, then overlaid with a new top surface. ($800,000). July-August.

• County Road 7, Hugo and Grant: Reclaim or cold-in-place recycle from the county line east to Irish Avenue ($2.4 million). Cold-in-place recycling is an eco-friendly method of rehabilitating pavement without heat, Slagle said. The top crust of pavement is removed, pulverized, mixed with an oil emulsion, then comes out looking like new as part of the repaving. August-September.

The county is funding $1 million of the $11.7 million in road work at Hwy. 36 and Hilton Trail..

• County Road 9, Grant: Repaving from County Road 7 south to Hwy. 96 ($1.1 million). Late summer.

• County Road 12 (75th Street N.), Mahtomedi and Willernie: Intersection improvements at Hwy 244 ($50,000). April.

• County Road 36 — to be renamed County Road 29 (Hilton Trail N.), Mahtomedi: Construct center left-turn lane at 72nd Street N. ($2500). July-August.

• County Road 23 (Orleans Avenue), Stillwater: Remove and replace pavement from Third Street to Fourth Avenue ($325,000). June-August.

• County Roads 62 and 63 (62nd Street N. and Oxboro Avenue N.), Stillwater: A variety of pavement, sign, alignment and trail projects to improve access to the Washington County Government Center and nearby residential areas, churches, schools and businesses ($2.5 million). June-August.

• County Road 21 (Stagecoach Trail), Afton: Replace the bridge over Valley Branch Creek ($450,000). June-September.

• County Road 19 (Woodbury Drive), Woodbury: Reconstruction from Eagle Valley Drive to half-mile south of County Road 18 (Bailey Road). Construction will be in two phases to minimize traffic disruption. The first phase runs from April to July between Eagle Valley Drive south to just past Lake Road — the intersection of Woodbury Drive and Lake Road will be closed. The second phase runs from August to November, when the intersection of Woodbury Drive and Bailey Road will be closed. A third phase to install a water reuse system at Eagle Valley and Prestwick golf courses won't affect traffic. ($9.9 million).

• County Road 13 (Radio Drive), Woodbury: Reconstruction from Bailey Road to Hargis Parkway, and full-depth reclamation from Hargis Parkway to Military Road ($2.7 million). May-July.

• County Roads 19, 20, 22 (Keats Avenue S., Military Road, 70th Street S.), Cottage Grove: This project will consolidate these two closely spaced intersections by removing the full-access intersection of County Road 20 and County Road 19. County Road 22 will be extended east of County Road 19 and connect with County Road 20 near old Cottage Grove ($7.8 million). May-November.

• County Road 76 (90th Street S.), Denmark Township: From Hwy. 95 to County Road 21 (St. Croix Trail), the entire length of the road will be repaved. ($1 million). Late summer.

County Road 19A (Innovation Road), Cottage Grove: Overlay south of Hwy. 61. May-June.

Work on the St. Croix Crossing, led by the state Department of Transportation, will also affect several county roads.

The county will also be a partner with MnDOT on several other projects. It is funding $1 million of the $11.7 million Hilton Trail/Hwy. 36 project, which will replace the stoplight with a freeway-style interchange.

MnDOT is also spending $1.6 million to build a roundabout in Hugo at the junction of Hwy. 61 and County Road 4 (170th St.), and the county is chipping in $40,000.

Jim Anderson • 651-925-5039; Twitter: @StribJAnderson