Stages of a River - Shubenacadie EarthCache

Stages of a River - Shubenacadie

The official full name of the lake is “Shubenacadie Grand Lake”  which helps distinguish it from other bodies of water in Nova Scotia with similar names.The lake is often simply called “Grand Lake” by locals. It is also called in Mi’kmaq, which literally translates to “grand lake”.  Shubenacadie Grand Lake drains into the Shubenacadie River at its northeastern outlet. The Shubenacadie River has a meander length of approximately 72 km from its source at Shubenacadie Grand Lake to its mouth at the historic seaport village of Maitland on Cobequid Bay. The Mi’kmaq have traversed the Shubenacadie River and the lakes to its south as a major transport route since time immemorial. Artifacts found along the waterway date back over 4,000 years, with some suspected to be much older.

Stages of a River

Nearly all rivers have an upper, middle, and lower course. The beginning of a river, when it flows quickly with lots of energy, is called a young river. The river here is smaller and usually has a rapid, tumbling flow that cuts a narrow channel through rocky hills or mountains. The fast flowing river can create waterfalls where it carves out layers of soft rock and leaves a cliff of hard rock standing.

The middle of a river’s journey, when it gets wider and slows down, is called the middle age. Rivers often meander (follow a winding path) along their middle course.  The current of the river no longer has the force to carry stones or gravel. This material drops to the riverbed, where it forms bars of sand or gravel or builds islands.

When the river reaches the end of its journey, it is called an old river. The end of the river is called the mouth. At the mouth, there is often a river delta, a large, silty area where the river splits into many different slow-flowing channels that have muddy banks.

Zone 1 Headwaters - Shubenacadie Grand Lake

Grand Lake is a large, deep lake which drains 59 named lakes and numerous streams. The lake is largely viewed as two sections. The main lake extends from Wellington in the South to the narrows between Walsh Point and Horne Settlement. The second section is the area known as “Little Grand Lake” which is the large embayment at the North end of the lake. These sections differ in surficial geology with the main lake dominated by metamorphic slates and greywacke while Little Grand is primarily sedimentary carbonates and evaporites. Thus, the main lake offers primarily rock cover while Little Grand offers primarily aquatic vegetation cover.

Zone 2 Transfer Zone - Shubenacadie River

The upper river is narrow, rocky, and winding until the area between Milford and Shubenacadie, where the increasingly muddy waters meet the influence of the tide, and the river widens. Through the middle portion there are expansive views of rolling farmland.

The lower 30 km of the river (from the point where the Stewiacke River converges with the Shubenacadie to the mouth of the Shubenacadie) is tidal. During this section the river experiences a tidal bore twice daily, with some bores reaching up to 3 m in height at certain points along the river. Numerous cliffs and rapids are also present in the last 30 km to the mouth of the river.

Sandbars are numerous in the lower river, and with the movement of the tides often makes the water turbulent and hard to predict. A bar in a river is an elevated region of sediment (such as sand or gravel) that has been deposited by the flow. The locations of bars are determined by the geometry of the river and the flow through it. Bars reflect sediment supply conditions, and can show where sediment supply rate is greater than the transport capacity.

Zone 3 Depositional Zone - Shubenacadie River Mouth

The mouth of the river is broad with low, sloping sides with large areas of mud flats along the shoreline. Mudflats or mud flats, also known as tidal flats, are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and aquatic animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily. Sediment is transported by the river and deposited, mid channel, at the mouth of the river. This occurs because, as the river widens at the mouth, the flow slows, and sediment settles out and is deposited.

With relatively shallow mudflats throughout the upper reaches of Cobequid Bay this impedes the initial advance of the rising tide at the Shubenacadie River mouth. The tidal bores are generated when the rapid rise in tidal elevation meets resistance from the ebb flowing water exiting the river. From Grand lake to the mouth of the river plus all the tributaries make for a steady strong flow of water to the Cobequid Bay. Thus the deposits and flow of the Shubenacadie, make it one of the unique rivers on the Bay of Fundy with a tidal bore.

To log this Earthcache visit the viewing location. Please answer the following questions and send in a timely manner to my geocaching profile or email. Answers not received will result in deleted logs.

Questions:

1. At Wellington Park, measure the distance from N44° 51.839' W63° 37.466' (Ref A) end of lake at N44° 58.478' W63° 34.415' (not accessible). What stage of the river is this?

2. At Enfield N44° 55.901' W63° 32.048' (Ref B), what stage of the river is this and why?

3. At Shubenacadie Park N45° 05.375' W63° 24.395' (Ref C), what stage of the river is this and why?

4. At Caddell Rapids Look-off N45° 11.907' W63° 23.425' (Ref D), what stage of the river is this and why?

5. At South Maitland N45° 14.999' W63° 27.426' (Ref E), what stage of the river is this and why?

6. At Maitland Wharf  N45° 19.311' W63° 29.969' (Ref F), what stage of the river is this and why?

7. Post a picture in your log with a personal item or hand in picture to prove you were there. At least at one site, if not more to prove your were there.

[REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please provide a photo of yourself or a personal item in the picture to prove you visited the site.