Talk to a few different landscape architects and compare services and estimated costs.

If I understand your situation, you must first have a topographical survey of the existing conditions, including boundaries and any other legal or key features such as easements, set backs, etc.

Once the existing features are confirmed, thereafter a site plan with needed improvements can be designed and the new topographical, drainage and other necessary features can be placed.

A land surveyor or civil engineer (who will sub out the surveying) can identify existing features.

For a creative and appropriate site development and improvement plan, however, you need someone who knows that end of the business--a landscape architect or your architect who designs your house.

Don't scrimp on this--it's important!

They are both needed. The person designing grading must have the topo survey in order to produce the grading plan. A topo survey is of existing grade. One must have that information in order to rework the topo lines in order to accommodate the site improvements. You would most likely get one bill for grading design of the site as long as areas were done at the same time, but the one performing the work could break out areas in order to calculate how much they would bill in total. While an engineer and landscape architect would both design according to established utility standards (like drainage), it's more likely that a landscape architect will put more emphasis on beauty and ease of maintenance.

Thank you for all your help! This helps to clarify the process.

Would a land surveyor be able to produce both the topographical survey and grading plan? Or would I need to hire the work out separately?

From what I understand, a topo is produced by a surveyor.

The grading plan by a civil engineer or landscape architect?

Also, on a separate note: will I need to also hire a structural engineer for "approval" of new garage foundation and slab and prefab garage? Or would I only need this if the township requires it?

Thank you so much for bearing with me! This process is new to me.

My topo was available to a decent degree by using the GIS survey available online at my county. Then, my surveyor (brother) validated it, helped me place the house and the final floor elevation, plotted the specimen trees, etc.

East coaster, what you described is how it works in my area.

Land Surveyor produces the topo/surface

Engineer or Architect produces site plan (usually an Architect, tho)

Engineer or Landscape Architect uses the survey to produce a grading plan for the proposed site plan.

They want to be sure you don't create a dam that blocks drainage and fills your house or your neighbor's. It really is important.

Thank you all very much for your input! I really appreciate it - helps to "un-murky" the waters for me in this uncharted territory.

Most states have laws that require any survey work be performed by a licensed surveyor. They can do a simple boundary line survey or a survey that includes existing contours which is what you need.

Once you have a survey with existing contours in hand, you'll need to produce a site development plan showing the driveway and garage footprint (and most likely the existing home for reference) and a strategy for managing storm water. Depending on the specific requirements for your property, the storm water management might involve simply grading the site to move storm water away from buildings or it might require the design of storm water management features such as water gardens, retention swales, etc. The design of the grading and storm water features isn't rocket science, but your municipality may require they be designed and sealed by a professional surveyor or engineer.

The survey firm we use has both licensed surveyors and engineers on staff and is a "one stop shop" for everything from the basic survey to the design of storm water management features. If there are any issues we only need to work with a single entity.

You all have been so helpful - thank you, everyone, for your expertise/input!