How do landscapers analyze sites?

Locating Utility Lines in a Landscape

­It shouldn't be too difficult to find the utility lines in a landscape. Just look up -- they're the black things strung between the telephone poles, right?

Not so fast. Any landscape analysis should take those lines into account -- especially when planning tree patterns and growth. But there's a lot more to consider. A garden isn't just empty­ land; it's land surrounding a home. That means it can contain all sorts of things that serve a home, such as:

  • Sewer and septic systems
  • Gas lines
  • Electrical lines and underground transformers
  • Cable TV lines
  • Water pipes
  • Telecommunications lines

For the most part, your local utility companies should be able to tell you where these lines are buried. However, if you've added underground utility lines yourself -- such as irrigation tubes or a gas line for the outdoor grill -- you're responsible for keeping track of their locations.

Your landscaper should check several standard depths:

  • At one foot down (30 cm) -- sometimes even less -- you might encounter cable lines and telephone lines in conduit.
  • At two feet down (61 cm), you could see electricity, sewage and telephone lines without conduits.
  • At three feet down (91 cm), are more electrical lines, water pipes and sewer lines.
  • At any depth, you might encounter gas lines. They don't have a standard depth [source: Lerner].

The landscaper should also consider the land's erosion patterns. Even gardens can lose major amounts of soil -- which could mean the gas line you think is 24 inches (61 cm) down is actually only 8 inches (20 cm) away from your shovel's blade.

­In addition, any landscape plan must take into account above-ground utility points, which might include electric, gas or water meters, transformers, heat pumps or guy wires.

Finally, remember the utilities that might be adjacent to your property -- sidewalks, curbs, right-of-way areas and so on. A landscape analysis must take into account common use, as well as any state and local ordinances that apply to these features. You could face a fine -- or the wrath of your neighbors -- if a tree drops a lot of fruit onto the sidewalk. And if your hedge is blocking visibility, it might be dangerous to drivers.

After looking at what's already below the ground, a landscape analysis should proceed to what's growing in the ground. Read on.