In hillslope geomorphology, a rill is a shallow channel cut into soil by the erosive action of flowing water. Similar but smaller incised channels are known as microrills. Artificial rills are channels constructed to carry a water supply from a distant water source. In landscape or garden design, constructed rills are an aesthetic water feature. Rills are shallow channels which are eroded into unprotected soil by hillslope runoff. Since soil is left bare during agricultural operations, rills may form on farmland during these vulnerable periods. Rills may form when bare soil is left exposed following deforestation, or during construction activities. Rills are easily visible when first incised, so they are the first indication of an ongoing erosion problem. Unless soil conservation measures are put into place, rills on eroding areas may develop into larger erosional features such as gullies or into badlands. Rills are created when water erodes the topsoil on hillsides, so are affected by seasonal weather patterns.
They tend to appear more in rainier months. Rills begin to form when the runoff shear stress, the ability of surface runoff to detach soil particles, overcomes the soil’s shear strength, the ability of soil to resist force working parallel to the soil’s surface; this begins the erosion process as water carries them down the slope. These forces explain why sandy, loamy soils are susceptible to the formation of rills, whereas dense clays tend to resist rill formation. Rills cannot form on every surface, their formation is intrinsically connected to the steepness of the hillside slope. Gravity determines the force of the water, which provides the power required to start the erosional environment necessary to create rills. Therefore, the formation of rills is controlled by the slope of the hillside. Slope controls the depth of the rills, while the length of the slope and the soil’s permeability control the number of incisions in an area; each type of soil has a threshold value, a slope angle below which water velocity cannot produce sufficient force to dislodge enough soil particles for rills to form.
For instance, on many non-cohesive slopes, this threshold value hovers around an angle of 2 degrees with a shear velocity between 3 and 3.5 cm/s. After rills begin forming, they are subjected to variety of other erosional forces which may increase their size and output volume. Up to 37% of erosion in a rill-ridden area may derive from mass movement, or collapse, of rill sidewalls; as water flows through a rill, it will undercut into triggering collapse. As water seeps into the soil of the walls, they weaken, amplifying the chance of wall collapse; the erosion created by these forces increases the size of the rill while swelling its output volume. Less dissolution of limestone and other soluble rocks by acidic rainfall and runoff results in the formation of rill-like features on the surface of the rock. Although rills are small, they transport significant amounts of soil each year; some estimates claim rill flow has a carrying capacity of nearly ten times that of non-rill, or interrill, areas. In a moderate rainfall, rill flow can carry rock fragments up to 9 cm in diameter downslope.
In 1987, scientist J. Poesen conducted an experiment on the Huldenberg field in Belgium which revealed that during a moderate rainfall, rill erosion removed as much as 200 kg of rock; the considerable effect rills have on landscapes negatively impact human activity. Rills have been observed washing away archaeological sites, they are very common in agricultural areas because sustained agriculture depletes the soil of much of its organic content, increasing the erodibility of the soil. Agricultural machines, such as tractors, compact the soil to the point where water flows over the surface rather than seeping into the soil. Tractor wheel impressions channel water, providing a perfect environment for the generation of rills. If left alone, these rills may erode considerable amounts of arable soil. Under proper field management rills are small and are repaired by contour tilling the soil; this will prevent, for a time at least, the rills from growing and eroding the landscape more with time. Aqueduct Chute Flume Gully Leat Pedosphere Zanja Madre
Henry Robinson was an English professional footballer who played as an outside forward. He grew up in Chilton, County Durham, as a youth played for the Chilton School team. Robinson went on to assist Kirk Merrington, Shildon Athletic and Chilton Colliery Railway before joining Football League First Division side Sunderland on amateur terms in September 1929. Although he was awarded a professional contract the following month, he failed to break into the first team and spent the entire season playing with the reserves in the North Eastern League. Robinson was signed by Third Division North club Nelson, he made his senior debut for Nelson in the opening match of the 1930–31 season, a 4–5 defeat away at Rochdale on 30 August 1930. Robinson scored his first Football League goal on 20 September 1930, netting his side's first in a 2–2 draw with New Brighton at Seedhill, he was on the scoresheet again four games in the 2–4 defeat to Crewe Alexandra. Robinson kept his place in the first team for most of the first half of the season, although Archie Howarth and Tom Carmedy played at outside-left occasionally.
On 20 December 1930 he scored his third goal of the season, a penalty kick, in the 2–0 win against Wrexham. Nelson progressed to the second round of the FA Cup in the 1930–31 campaign and Robinson played in all three matches, scoring once, he made his final appearance for the club on 24 January 1931 as Nelson were beaten 0–2 at New Brighton. In February 1931, Robinson was released by Nelson along with several other players because of financial problems at the club, he spent the remainder of the season with Hartlepools United, where he scored one goal in six league games. In the summer of 1931 he returned to the North Eastern League with Spennymoor United. After spending the 1931–32 season with the County Durham club, Robinson was offered a short-term contract by Darlington, he signed for the Quakers in August 1932, marking a return to the Third Division North, but played only one first-team game before leaving the club the following month. Robinson subsequently had spells in non-League football with Crook Town and Horden Colliery Welfare before retiring from football
Enzo Roberto Díaz is an Argentine professional footballer who plays as a forward for Club Atlético Tigre. Díaz started his career in the youth system of Vélez Sarsfield, prior to having a stint with Santamarina. Díaz began his senior career with Jorge Newbery de Lobería in Liga Necochense, before signing for Primera B Metropolitana's UAI Urquiza on 11 August 2016, he scored on his professional debut on 26 August against San Telmo, followed by another goal in his next appearance versus Almirante Brown. Díaz finished the 2016–17 campaign with eight goals, he netted fifteen times with the goals being spread across fourteen fixtures. On 30 June 2018, Díaz completed a move to Ferro Carril Oeste of Primera B Nacional. Six goals followed across his opening twelve appearances, with the forward concluding the campaign with fourteen goals; as of 24 May 2019. Enzo Díaz at Soccerway