OBJECTIVE OF THE ZONOLITE PARK RIPARIAN PILOT

Nickel Bottom Garden: Riparian Barrier

The bank of the South Fork of the Peachtree Creek, within Zonolite Park, varies significantly – from deeply eroded high banks of 10 feet or more to shallower sand banks of 4-6 feet. No part of the creek banks are stable with vegetation that eliminates or mitigates the continuous march of bank erosion.

The focus of this pilot project is on creek banks that are less than 6 feet high. The objectives of the pilot project are; remove invasive Japanese Hops Vines, restore part of the riparian barrier to learn restoration techniques and identify plants that can be successfully introduced. Specifically, we hope to learn:

  • With heavy rains, when the planted area floods, did the plants survive, or were they washed away? Did some plants survive better than others?
  • Did the Japanese Hops Vine that were hand pulled come back?
  • Did the live stakes grow roots and thrive?
  • If the live stakes grew – did some types of trees/shrubs work best?
  • Were we able to transplant riverswitch cane successfully?
  • What were the advantages and disadvantages between live stakes and the transplanted cane?
  • Did native grasses grow from plants? plugs?
  • Which grass varieties grew best – and were there differences between – plants and plugs?
  • Did the perennials grow and thrive? Which ones did best?
  • Did the trees and shrubs grow and survive? Which ones did best?
  • Did the jute mat help the plants survive?
  • Did the combination of the jute mat and staking help the plants survive better than just using the mat?
  • What was the difference in survival rates for the plants where neither the jute mat or staking were used?
  • Did people and dogs have any negative impact on the restoration? Did they go around the fence and did it matter?

We expect it will take a year or longer to get answers to many of the above questions. The intent is to review this document and document the results to create a baseline that can be used to assist in creating future plans – for other parts of the park.

Restoration Plan

The restoration plan is to plant trees and shrubs along the current bank face, in an attempt to stabilize or define the current bank as a “new” bank – to stop the significant eroding that has occurred in the last 18 months as the creek channel has changed with several large trees falling in to the creek.

Next to the trees and shrubs we will plant a mixture of native grasses and perennials. We will also plant Swamp Milkweed in groups of 3 or 4. We will create a 3-4 foot wide trail in the middle that will eventually allow you to walk from the creek, thru the re-planted area up to the waterfall.

We will divide some of the very large perennials planted in the pollinator garden at the entrance, such as Joe Pye Weed along the trail. Lastly, we will plant additional trees to strengthen the existing larger tree line along the tree bank. The restoration plan has 7 areas or zones. A more detailed summary is the below table.

Creek

Live stakes are pounded in to the creek bank at an angle – we planted 175 stakes with an equal mixture of Black and Silky Willow and Elderberry – roughly 58 stakes of each. We will also transplant river/switch cane along about 15 feet of bank. We will transplant river cane from within the park where there is a single plant.

At the top of the bank, in the shaded area , we will plant Silky Dogwood and Button Bush – roughly 6 feet apart.

In two strips – each roughly 8-10 feet wide, on each side of a trail, we will plant native grasses and perennials. We will plant many small plugs of native grasses. We will plant Butterfly and Swamp Milkweed and Little Joe Pye Weed – in 4 or 5 clusters within the grasses.

The trail will wind from where the existing trail meets the creek bank, thru the restored area up to the bowl below the waterfall.

We will plant a 4-5 foot strip of large perennials that we will transplant from the pollinator garden. The plants, and how many, will depend on what needs to be thinned in the pollinator garden.

We have several small saplings of Redbuds and Red Maples. If the budget permits we hope to plant 7-8 larger trees.

Design of the Pilot

It is intended for this pilot to follow the guidance provided by Georgia’s EPD. Links to two detailed EPD documents are below. While the documents define several techniques depending on the nature of the restoration – the only technique used in this pilot is “live staking.”

Useful Links

Research on Japanese Hops

Interesting article on Arundinaria gigantea – also called giant cane or river cane. Switch Cane is a subspecies. This is the only bamboo native to North America. The article also postulates a strategy of growing giant cane with native grasses such as big bluestem and Indian grasses – for they have different growth patterns.

Georgia’s EPD guidelines for streambank restoration (PDF download)

Georgia’s EPD guidelines for streambank and shoreline stabilization (PDF download)

Grade Control Structure Presentation From Colorado State

A Guide to Bank Restoration Options for Large River Systems: Part II Bioengineering Installation Manual

Suppliers Used for Plants:

Mellow Marsh Farms

Mid Atlantic Natives