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Waterway and wetland permits: part I - management of aquatic plants and algae in ponds

Purpose of this booklet

This booklet provides practical information and techniques to manage or limit aquatic plants and algae if they reach a nuisance level in ponds. It will aid you in forming realistic expectations of what a pond can and cannot be. This booklet also attempts to raise your awareness of when to call in professional help, what regulations apply to ponds and when you will need permits. The booklet discusses some basic concepts for designing ponds; it does not go into detail on construction techniques. The reference section of this booklet contains additional information sources on pond construction.

Disclaimer: The information in this booklet is intended solely as guidance and does not include any mandatory requirements except those found in statute or administrative rule. The information does not establish or affect legal rights or obligations and is not finally determinative for any regulatory decisions related to the contents of this booklet. The information does not create any rights enforceable by any party in litigation. Any regulatory decisions made by state or local agencies will be made by applying the governing statutes, administrative rule and common law decisions of controlling courts.

Throwing the baby out with the bath water

Before you decide to build a pond, take a long hard look at whether or not a pond will improve habitat or destroy the vital wetlands on your property. Most folks that are considering building a pond want to build on wetland sites. In these cases, habitat loss can easily outweigh any benefits a pond may bring.

Be realistic with expectations for your pond. Try and use techniques that blend with natural processes rather than those that resist them. A pond is a complex biological system. When we tinker with one or build one from scratch, it might be wise to acknowledge the limits of human understanding.

What is a pond?

Where does a puddle end and a pond begin? Webster gives a vague definition of a pond as "a body of standing water smaller than a lake." This booklet will generally refer to ponds as a waterbody containing water year-round and smaller than 10 acres in size.

Ponds may be natural or created by people. The physical characteristics and the ownership of a pond can play a role in defining a pond for regulatory purposes and for determining management options.

In Wisconsin, nearly all waterbodies are legally defined as waters of the state; see Section 281.01, Wis. Stats. Because they are waters of the state, ponds are under the jurisdiction of the Wisconsin Department of Natural Resources (DNR) even though they may be located on private land. Therefore, DNR permits or approvals are required for most management strategies highlighted in this booklet.

If you are considering a wildlife pond, contact a local DNR wildlife biologist or other wildlife experts to discuss your ideas. Many times there may be alternatives to pond building a pond that can provide beneficial habitat and meet your needs and, at the same time, save you considerable time and money. A factsheet available from the DNR titled "Managing Stream Corridors for Wildlife" (#PUB-WM-225, 410KB) provides greater detail about managing your nearshore wildlife habitat.

What you can expect

Every pond has a unique set of characteristics that will determine what you can realistically expect from it. Ponds (old or new) cannot be everything for everybody. They may not always be ideal for a fishing hole, wildlife area, or swimming pool. A pond that is aesthetically pleasing to one person may not be to another. Although a pond may provide multiple uses when first constructed, unforeseen transformations may arise. Over a ten-to-twenty-year period the accumulation of leaf matter, lawn clippings, fertilizer and sediment may lead to excessive plant and algae growth and changes in water clarity. There may be a variety of transformations to fish populations, including change in size, species or even winterkill. Remember, physical characteristics, location, and water source will ultimately decide the appearance of your pond. The true characteristics of your pond will be more apparent with age.

Designing your pond


The very first step of pond management is to decide what type of pond you want to create or what can be done with an existing pond. This should be decided, in part, by the inherent characteristics of your pond. Your list of expectations for the pond may be long. The key is matching your expectations with those defined pond characteristics (see Table 1: Designing Your Pond). The objectives you set for your pond will, in large part, determine the amount of aquatic plant and algal growth that you will find to be acceptable. Take the time to visit other ponds in the area to get an idea of what you can expect.

Table 1: Designing Your Pond
Pond type Characteristics Aesthetics Boating Fishing Swimming Wildlife
Wildlife Heavy vegetation, with extensive buffer strips. Generally shallow (<3 feet) with an irregular, gentle sloping shoreline. X X ^
Fishing Moderate vegetation (30% to 50%). Generally steeper drop-offs and deeper (>10 feet), although with groundwater or surface flow may be shallower (<5 ft). Side slopes of 3:1 will provide habitat. ^
Swimming Minimal vegetation (<10%) with gradual slopes and firm bottom. Typically mowed shoreline in the swimming area with major buffer strips in the rest of the pond to limit runoff and promote water quality in the swimming beach area. Side slopes of 4:1 or 5:1. X ^ X
Commercial May include ornamental ponds or industrial cooling ponds. Vegetation (<40%) with variable depths and sizes. X X X X
Stormwater Designed to catch and hold run-off from subdivisions, parking lots, roads, or other urban areas. Physical characteristics vary, normally has an outflow. X X X X

Note: Ponds can provide many diverse uses, but their unique characteristics will determine what they are best suited for.


  • Exceptionally Suited: ^
  • Potentially Suited:—
  • Less Suited: X

Location, location, location

Each pond is unique. The types of soil, sources of the pond's water and how people are using the land near the pond and in its watershed will determine how quickly a pond ages. A pond situated in a watershed area with fertile soils or mowed shores may experience a more rapid succession of nuisance plant and algae growth than a pond in a nutrient-poor location. It stands to reason that a pond's water source will have a major influence on its water quality and appearance. If groundwater is the major water source, your pond will be somewhat protected from runoff problems and maintain cooler temperatures. If rainfall is the major water source, your pond will be impacted by runoff from land-use practices in areas sloping to your pond. If streams are the major water source, your pond will be affected by runoff from the stream's entire watershed. Take a look at the watershed (the area in which water will flow into your pond). If it is heavy with exposed soils, agriculture or other practices that cause nutrients to flow with the water running into your pond, it may very well suffer from excessive nutrient loading.

When will I need a permit?

When you apply for a state permit from DNR, your application will automatically be forwarded to the Army Corps of Engineers (ACOE) for federal permit processing. A factsheet available from the DNR titled "Waterway Permits for Ponds and Small Impoundments" (Publication #PUB-FH-056) details the types of permits that may be required. Generally, state law requires a permit for construction of a pond if any of the following conditions apply:

The Pond is within a wetland

Existing wetlands are usually self-sustaining ecosystems which provide fish and wildlife habitat, flood, water quality and shoreline protection as well as aesthetics and recreational opportunities. These systems should not be disturbed or altered to create deep water ponds for fishing or stormwater detention. Wildlife ponds can be constructed in an upland area that is adjacent to existing wetlands to avoid impacting these fragile ecosystems. Occasionally, wildlife ponds that are shallow (less than 5 feet deep) and gentle sloping (less than 1:8 slide slopes) may be built in lower quality wetlands where the construction will enhance the water quality and wildlife values of the wetland.

The pond is an enlargement of an existing navigable water

Construction of a pond that will ultimately be connected to a navigable waterway requires permits from DNR and ACOE. In Wisconsin, once a pond is connected to a navigable waterway by a navigable connection, it becomes a public waterway. Creating a pond by dredging, grading or constructing a dam in a navigable waterway requires DNR and ACOE permits. In most cases, an environmental assessment must also be prepared and a 30-day public notice is required. Constructing a warm water pond that discharges to a cold-water stream can be environmentally damaging and is difficult, if not impossible to permit.

The pond is within 500 feet of a navigable water

Ponds built in close proximity to a waterway may impact those sensitive ecosystems that provide critical habitat for fish and wildlife at the same time providing water quality benefits to the waterway. You will need to obtain permits from the DNR to construct a pond within 500 feet of any navigable waterway.

De-watering of a pond

De-watering means draining your pond. Drawing down or de-watering is a technique that can be used to compact sediments and, in some cases, to control aquatic plants by drying out the pond bed. De-watering of a pond may require a Water Pollution Discharge Elimination System (WPDES) permit. This can be obtained from DNR.

Forward to Part II | Forward to Part III