Simplified Grading for Garden Designers

Grading is a combination of art and science.  As landscape designers we should lean towards the art side and reinforce our solutions with the science.  We grade for patios and walkways, drainage and aesthetics. Our plans are our way of communicating our ideas with contractors and others who will build our designs. 

To be successful you need to know how to make changes in the existing topography properly and communicate these ideas to others.  In this lecture I'll introduce you to the basic concepts of what contours represent and of spot elevations.

Cross-sections are developed from contour and conceptual plans.  They can show you (or your client) changes in elevation and how the land and garden relate and connect within a predetermined view.  In this lecture I'll explain, show examples and demonstrate how to create a cross-section of your design.

Welcome to the end of this Section.  We'll be using the information learned in these 3 lectures as we move deeper into the course.  Let's do a quick recap of what we've covered so far.

One purpose of grading is to control drainage.  In essence we are creating swales and ridges and either moving water off-site or capturing it within our property.  in this lecture we'll look at the characteristics of swales and ridges.

Every landscape can be considered a mini-watershed.  We'll look at how we can define a watershed within our urban landscapes as well as watersheds in the wider environment.

We've covered a lot of ground in this Section.  With this lecture I'll do a quick recap of what we've discussed.  We'll finish with some exercises that will help reinforce what we've learned. 

Slope formula is fairly simple algebra that you'll use to not only calculate the percentage of slope, but also how to locate whole value contour lines in between spot elevations.  In this lecture I'll clarify how to use this formula.

In this lecture I have provided an exercise in Interpolation and Contour creation. Print size is either 8 1/2 x 11 or A4.  Each exercise has been scaled for feet and inches (imperial), tenths of a foot (engineer) and metric, so there is a plan for everyone!  I am also providing the solutions for each exercise - but give them a try before you jump to the answer! So, download the plan of your choice (or try all 3!) If you get lost, go back to lectures 9 & 10 for a refresher.  Good Luck!  Message me with any questions.

With this Lecture we'll carry on becoming familiar with using Slope Formula.  For this exercise I have provided you with one spot elevation, the length and the percent of slope.  Calculate what the unknown spot elevations are and again, find and draw in the contour lines where they would be found.  Plan is scaled in feet and inches, engineer's scale and metric.  Print size is 8 1/2 x 11 and A4.  Tip: You are looking for a Difference in Elevation (DE)!

Our last Slope Exercise for this Section.  In this exercise you are to create a topographic map from the spot elevations given.  This is a tricky problem - there is a twist to it and it's been a puzzle to many students over the years.  See if you can figure this one out.  Then...take a break!  This plan is in just two scale values - Engineers Scale and Metric Scale.  Print size is 8 1/2 x 11 and A4.  The Solution is provided - but don't peek!

A quick review of Section 3

This short lecture will touch on some basic rules when grading.  This information is available for download in the Resources for this lecture.  Be aware that starting with this section all of the exercises you'll be working on will be either in Engineers Scale or Metric Scale!  No more feet and inches (architects scale).

When we design a garden we're often including patios, paths and other surfaces that need to be flat enough to be used.  The existing ground is not always flat and that means we have to know how to graphically move dirt around to explain our ideas to contractors and clients.  In this lecture we'll have our first look at how we, as designers, can do this. 

When grading around a hard surface you can use ratios to quickly locate proposed contour lines within your design rather than always relying on the slope formula.  Let's see how that is done.

In this lecture we're taking the concept of a patio to a slightly larger context and we'll design a proposed tennis court on sloped ground.  We'll do this exercise twice - the slope will fall in first one direction and then we'll grade the site when the slope falls in another direction.  This will give you two different attempts at mastering contour manipulation!   The instructions are on a separate sheet, so be sure to download them as well!  I will provide two solutions for this exercise - two in engineers scale and two in metric, based on the direction of slope.  Print size is either 8 1/2 x 11 or A3.  Good luck!

When we design a garden we often include paths leading from one area to another.  But what if this means we have to go up or down a slope?  We want to maintain an accessible grade to make it easy for people of all ages to walk and in this lesson we'll do an exercise where you have to calculate the grade (in %) of a pathway, create a swale and avoid an existing tree as well.

In this lecture we'll return to our patio and look at different alternatives to grading the surface.  The main purpose of this lesson to demonstrate that you can always find another solution to a problem!  In Resources you'll find two plan drawings demonstrating grading alternatives.   Print size is 11 x 17 Imperial and A3 Metric.

In this lesson you'll be downloading a site plan showing a house, driveway, existing contour lines and existing trees.  You will need to grade the lot based on the instructions available on the exercise sheet.  You'll be using all you have learned to complete this exercise.  Good Luck!  Print size is 11 x 17 or A4

We have covered a lot of ground in this Section!  I would suggest that you revisit these exercises, especially if you had to look at the solutions to finish the assignment.  You might even change the slope percentage on some of them and try it again just for practice!

When doing your own elevation survey you'll need to own or rent a few basic tools, namely an elevation rod, builders level or transit and a tape measure.  In this lecture we'll go over these tools and how to use them.

When getting ready to conduct your elevation survey I highly recommend that you complete the site survey of the property first.  By completing this portion of the survey you will be able to create a scaled map of the property and better identify the critical points where you may need to take an elevation reading.  In this lecture we'll go over the basic steps in planning your survey.

A benchmark is a fixed location that should not be changed or altered and should be easily located if the survey needs to be revisited.  A professional surveyor may use an elevation that has been established by an official geological survey, but for garden designers we just need a permanent starting location that will not change any time soon.  In this lecture I'll offer my suggestions on what makes a good benchmark on a residential property.

Before you start setting up your instruments you need to know how to accurately record your information in a way that you'll be able to use later.  In this lesson I'll go over the leveling form and how to fill in the site data you'll be collecting.

Well, your survey is complete and you have a full sheet or more of rod readings from the field, now what?  Now we'll revisit the leveling form and using the assumed elevation at the benchmark we'll calculate our spot elevations.

Now that you have the spot elevations all calculated you can transfer this information onto your site survey and, using interpolation, create a topographic map of the property.  This is our final exercise in the course.  I've provided this using feet and inches (although the elevations will be in tenths of a foot) and metric scale.  You'll be doing some interpolation, drawing in your existing contour lines and designing a retaining wall tall enough to level the upper terrace area. You'll also get to design a set of steps to access the upper terrace.  Print size is 8 1/2 x 11 and A4.  The leveling form to use with imperial measurements is at the bottom of the Resources section.

I've included the solutions and a set of notes for further explanation.  So, choose the plan you prefer and good luck! 

We've discussed the tools you'll need and determined the purpose of the survey.  Now let's look at how to set up the level so you can get started.

We've covered a lot of ground in this course and I've introduced you to some challenging math.  I've found that having this basic understanding of elevations, contours and topographic maps has helped me to become a better designer.  Being able to discuss options with both owners and landscape contractors will give you greater credibility within the industry.  Remember, know your limits!  This course was not intended to make you a grading engineer - it is intended to broaden your understanding of how to deal with uneven terrain.  If a project looks to daunting then have the client hire a professional surveyor to provide you with a topographic map.  Good Luck!