LANDSCAPE DRAINAGE

Drainage and Erosion Problems, Dry Creek Beds, and Rain Gardens

In early May 2016, the Cary area received more than 4” of rain and hail in less than an hour. Yearly rainfall at the RDU airport for 2015 was over 10” more compared to 2014, resulting in extremely saturated soils in the winter of 2015-2016. If your landscape is not prepared for these weather events, your yard can take a beating. Add to these weather events…naturally poor draining clay soils, extremely compacted soils around your home due to heavy equipment during construction, more rainwater entering your property because of impervious materials being installed upstream, yards that are not graded properly, and you have the potential serious problems that can affect your pocketbook, lifestyle, your neighbors, and the resale of your property.

Drainage Problems

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Perhaps You Have One of the Following Situations

    • After a rain, water collects on the driveway, patio or walkway
    • Does rainwater rush across your yard creating gullies and washing away soil
    • Areas of your yard or lawn won’t drain. Water puddling that lasts over 24 hours because of lack of slope to the land or hard packed impervious soils, showing up especially in winter
    • Gutter downspouts don’t properly drain roof rain water to a safe location
  • Stream erosion
  • Complaints from your neighbors or HOA, concerning storm water exiting your property causing problems
  • You’re in a stream watershed, and need to meet certain government or HOA impervious surface requirements
  • You’re getting ready to do some major landscaping

What can you do? Before a thunderstorm hits, grab an umbrella, a camera and photograph any problems, your photos will be critical in helping Renz Landscapes solve your drainage problems.

Additional Information to Consider for Drainage Concerns

Watershed: This is the area, higher in elevation than your property that will collects rainwater that eventually flows on to your property. The larger the watershed, the heavier the rain and the more saturated the land, the greater the problem.

Dry Creek Beds: When fast and large amounts of storm water are flowing across your yard creating erosion, a dry creek bed, built with attractive rounded river rock, can channel the flow, eliminating erosion and creating something natural and attractive. The way the channel is created with different landscape materials and plants can be the difference between a strip of stone and an attractive piece of landscape that disguises the problem. Often a solution, compared to piping the rainwater underground or running it across a lawn or natural area.

Rain Gardens: Great idea for plant lovers. Rain gardens, simply a draing hole in the ground, collects and slow eroding rainwater before water volume and velocity has a chance to damage your landscape. An attractively shaped outline of the hole is critical so the garden looks like it belongs. The hole or depression is dug deep enough so most of the water is able to percolate into the ground as the hole fills with water. Partially backfilled with well drained soil and planted with a collection of water loving plants, excess water that doesn’t percolate, fills the hole with some water trickling out the lowest side of the hole sending some slower moving and smaller amounts of water on its natural course. It may be a better solution than underground piping or a dry creek beds. The added benefits are collecting sediment or loose soil, getting storm water back into the ground and out of streams, and creating an environment for water loving plants for all you plant lovers. The concept of building a rain garden may seem easy, but building it so it functions correctly, and aesthetically blends into the surroundings can be tricky.

French Drains: These are technically a fairly large dug hole where rain water might naturally collect, generally filled with 1-3” gravel. The idea being, the water will collect in the voids of the gravel and slowly move into more pervious soil at the bottom of the hole. However French drains don’t perform well in our piedmont soils because the soils in the Raleigh area and especially western Wake county and Durham are extremely impervious. What does work are catch basins and water collection trenches that that are connected to drain pipes installed underground, with at least 1% slope, allowing the water to exiting into an with an area with a lower elevation.

For you word buffs, the French Drain was not invented in France, rather is named after and popularized by Henry Flagg French (1813–1885) of Concord, Massachusetts, a lawyer and Assistant US Treasury Secretary, in his 1859 book Farm Drainage.

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French Drain

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Techniques & Materials to Handle Drainage Problems

    • Tripod level and survey rod to accurately determine land elevations
    • Terracing and retaining walls ~ installing sod ~ Installing groundcover plants
    • Installing proper mulching materials
    • Swales construction
    • Erosion diversion strips
    • Rain gardens
    • Dry creek beds
  • Knowledge of elevation drop needed to move water where you need
  • Proper drainage pipe sizing, based on square footage of your roof or watershed
  • French drains, downspout water collection
  • Catch basins with flat or atrium grates
  • Erosion dams
  • Erosion netting
  • Hydro seeding

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There is always a strong chance for thundershowers right around the corner, mosquitoes lurking, and a winter rain bringing moisture from the Gulf. Contact Renz Landscapes for a consultation, before you start any project, if you think you have a concern.