Most activities within your landscape will require level or nearly level land. In addition, your site drainage is one of the most important design issues to consider. In general, a slope between 0.5 and 5 percent will allow for recreational use while still allowing for site drainage. As you work through your design, try to locate the activity areas where existing slopes and grades conform as closely as possible to the requirements of the proposed activity. In cases where major modifications are required, additional time, materials and costs will certainly be incurred. Some complex grading and drainage projects may require a landscape architect or engineer's advice. The following article by Denver Landscape Architect, Ken Ball, gives some good hints about evaluating and improving your slope. "On the Level" - A Landscape Tip That'll Give You Passing Grades By Ken Ball, ASLA Do you want to move water through your landscape for water harvesting? Make your turf lawn areas appear flatter and be more functional? Have a better feel for the relative heights and elevations of various elements in your landscape? Here is an inexpensive and simple method that'll help you know which way is up! And, you can avoid your basement becoming the lowest (and wettest) point in the landscape. Required equipment:
- a line level ($2 at any good hardware store),
- a 100-ft. length of nylon survey cord ($3),
- and a tape measure ($10). Pin one end of the string at a high point on the ground, stretch the string taught, place the line level on the string, raise or lower the movable end of the string until the bubble is centered in the level, and measure the height the string is above the ground at the measure point. This will establish the grade the point just measured in the landscape has in relation to the pinned end of the string line. The change can be expressed in percent of slope over a known distance, or as a change in inches of elevation. 
For example, if the drop is four feet and the distance is eight feet the slope is 50 percent. If the drop is six inches and the distance is 10 feet (120 inches), the slope is 5 percent. Or, if the drop is six-tenths of an inch over 10 feet (120 inches), the slope is 0.5 percent. The maximum slope for a functional use of turf area is 5 percent, the minimum 0.5 percent (without risking formation of puddle areas). Functional use may be defined as noncompetitive games and recreation. Repetitively measuring distances and heights, digging and filling areas with soil, the flow of moisture around, across and through the landscape can be controlled. Controlled flow permits moisture to beneficially soak into the soil in planted areas. Controlled flow also reduces rapid discharge of water from the site that adds to the community's storm drainage problem. On the other hand, flow of moisture off the site when torrents of precipitation occur must be assured to prevent the risk of flooding to structures on the site. Be aware of how water may flow onto your site from other locations, too. Proper site drainage is one of the most important design parameters to be considered as part of every landscape plan. | 
