diff --git a/Applications/FileIO/Gmsh/GMSHLineLoop.h b/Applications/FileIO/Gmsh/GMSHLineLoop.h
index d6e1522f60473a10eb33395a10fa7c2eb60ca36f..38df94f28d48acc12272643d70de9838d640bfee 100644
--- a/Applications/FileIO/Gmsh/GMSHLineLoop.h
+++ b/Applications/FileIO/Gmsh/GMSHLineLoop.h
@@ -26,7 +26,7 @@ public:
     virtual ~GMSHLineLoop();
     bool isSurface() const { return _is_sfc; }
     void setSurface(bool is_sfc) { _is_sfc = is_sfc; }
-    void write(std::ostream& os, std::size_t offset,
+    void write(std::ostream& os, std::size_t line_offset,
                std::size_t sfc_offset = 0) const;
 
 private:
diff --git a/Applications/FileIO/PetrelInterface.h b/Applications/FileIO/PetrelInterface.h
index 6606bdc70909c3957ebf7e0224be3fcac1b71190..3324b079e700b7261ba27159fe101d2150db2707 100644
--- a/Applications/FileIO/PetrelInterface.h
+++ b/Applications/FileIO/PetrelInterface.h
@@ -37,7 +37,7 @@ public:
     PetrelInterface(std::list<std::string> &sfc_fnames,
                     std::list<std::string> &well_path_fnames,
                     std::string &unique_model_name,
-                    GeoLib::GEOObjects* obj);
+                    GeoLib::GEOObjects* geo_obj);
 
     PetrelInterface(PetrelInterface const& other) = delete;
     PetrelInterface(PetrelInterface&& other) = delete;
diff --git a/GeoLib/GEOObjects.cpp b/GeoLib/GEOObjects.cpp
index c6830eeae007e13d72f4cae98fd4f1ba6c0b6b79..d45a6eb65a5351fbac3d355e165ce6d4eb2ba524 100644
--- a/GeoLib/GEOObjects.cpp
+++ b/GeoLib/GEOObjects.cpp
@@ -415,8 +415,8 @@ std::string GEOObjects::getElementNameByID(const std::string& geometry_name,
     return name;
 }
 
-int GEOObjects::mergeGeometries (std::vector<std::string> const & geo_names,
-                                 std::string &merged_geo_name)
+int GEOObjects::mergeGeometries(std::vector<std::string> const& geo_names,
+                                std::string& merged_geo_name)
 {
     const std::size_t n_geo_names(geo_names.size());
 
@@ -538,7 +538,8 @@ void GEOObjects::mergeSurfaces(std::vector<std::string> const& geo_names,
     const std::size_t n_geo_names(geo_names.size());
     std::vector<std::size_t> sfc_offsets(n_geo_names, 0);
     auto merged_sfcs = std::make_unique<std::vector<GeoLib::Surface*>>();
-    std::unique_ptr<std::map<std::string, std::size_t>> merged_sfc_names;
+    auto merged_sfc_names =
+        std::make_unique<std::map<std::string, std::size_t>>();
     for (std::size_t j(0); j < n_geo_names; j++) {
         const std::vector<GeoLib::Surface*>* sfcs (this->getSurfaceVec(geo_names[j]));
         if (sfcs) {
diff --git a/GeoLib/GEOObjects.h b/GeoLib/GEOObjects.h
index a9ff7b3f3c729bfa31180a5518325747897aa3d3..7ef08bc47d8ca057688088adc6ab2233c8fd3453 100644
--- a/GeoLib/GEOObjects.h
+++ b/GeoLib/GEOObjects.h
@@ -242,11 +242,12 @@ public:
     /**
      * Method mergeGeometries merges the geometries that are given by the names in the vector.
      * Stations points are not included in the resulting merged geometry.
-     * @param names the names of the geometries that are to be merged
+     * @param geo_names the names of the geometries that are to be merged
      * @param merged_geo_name the name of the resulting geometry
      * @return 0 if success, 1 if no point-list is found for at least one of the geometries and 2 if the mergelist only contains less than two geometry
      */
-    int mergeGeometries(std::vector<std::string> const & names, std::string &merged_geo_name);
+    int mergeGeometries(std::vector<std::string> const& geo_names,
+                        std::string& merged_geo_name);
 
     /// Renames an existing geometry, i.e. renames the internal PointVec,
     /// PolylineVec and the SurfaceVec objects from \c old_name to \c new_name.
diff --git a/GeoLib/Grid.h b/GeoLib/Grid.h
index f5eebc3bb82f58d593e307e7c065fb6d155b98a6..5a56cbab60e746947ba9a696eb701c132f33704d 100644
--- a/GeoLib/Grid.h
+++ b/GeoLib/Grid.h
@@ -404,18 +404,24 @@ std::array<std::size_t,3> Grid<POINT>::getGridCoords(T const& pnt) const
 
 template <typename POINT>
 template <typename P>
-std::array<double,6> Grid<POINT>::getPointCellBorderDistances(P const& p,
+std::array<double,6> Grid<POINT>::getPointCellBorderDistances(P const& pnt,
     std::array<std::size_t,3> const& coords) const
 {
     std::array<double,6> dists{};
-    dists[0] = std::abs(p[2]-_min_pnt[2] + coords[2]*_step_sizes[2]); // bottom
-    dists[5] = std::abs(p[2]-_min_pnt[2] + (coords[2]+1)*_step_sizes[2]); // top
-
-    dists[1] = std::abs(p[1]-_min_pnt[1] + coords[1]*_step_sizes[1]); // front
-    dists[3] = std::abs(p[1]-_min_pnt[1] + (coords[1]+1)*_step_sizes[1]); // back
-
-    dists[4] = std::abs(p[0]-_min_pnt[0] + coords[0]*_step_sizes[0]); // left
-    dists[2] = std::abs(p[0]-_min_pnt[0] + (coords[0]+1)*_step_sizes[0]); // right
+    dists[0] =
+        std::abs(pnt[2] - _min_pnt[2] + coords[2] * _step_sizes[2]);  // bottom
+    dists[5] = std::abs(pnt[2] - _min_pnt[2] +
+                        (coords[2] + 1) * _step_sizes[2]);  // top
+
+    dists[1] =
+        std::abs(pnt[1] - _min_pnt[1] + coords[1] * _step_sizes[1]);  // front
+    dists[3] = std::abs(pnt[1] - _min_pnt[1] +
+                        (coords[1] + 1) * _step_sizes[1]);  // back
+
+    dists[4] =
+        std::abs(pnt[0] - _min_pnt[0] + coords[0] * _step_sizes[0]);  // left
+    dists[2] = std::abs(pnt[0] - _min_pnt[0] +
+                        (coords[0] + 1) * _step_sizes[0]);  // right
     return dists;
 }
 
diff --git a/GeoLib/OctTree-impl.h b/GeoLib/OctTree-impl.h
index 42cc4583dada32e2a5b7a8c43b53c8b059327040..7319743b3bcd703d582e9e7126f8300d39d1e655 100644
--- a/GeoLib/OctTree-impl.h
+++ b/GeoLib/OctTree-impl.h
@@ -72,14 +72,14 @@ bool OctTree<POINT, MAX_POINTS>::addPoint(POINT * pnt, POINT *& ret_pnt)
     MathLib::Point3d max(
         std::array<double,3>{{(*pnt)[0]+_eps, (*pnt)[1]+_eps, (*pnt)[2]+_eps}});
     getPointsInRange(min, max, query_pnts);
-    if (! query_pnts.empty()) {
-        // check Euclidean norm
-        for (auto p : query_pnts) {
-            if (MathLib::sqrDist(*p, *pnt) <= _eps*_eps) {
-                ret_pnt = p;
-                return false;
-            }
-        }
+    auto const it = std::find_if(
+        query_pnts.begin(), query_pnts.end(), [pnt, this](auto const* p) {
+            return MathLib::sqrDist(*p, *pnt) < _eps * _eps;
+        });
+    if (it != query_pnts.end())
+    {
+        ret_pnt = *it;
+        return false;
     }
 
     // the point pnt is not yet in the OctTree
diff --git a/GeoLib/Polygon.cpp b/GeoLib/Polygon.cpp
index 29f495cb372de68e591027b118b9d4771f108f88..5c55877ec65acaf42e070521a15c6ed3279096d9 100644
--- a/GeoLib/Polygon.cpp
+++ b/GeoLib/Polygon.cpp
@@ -244,12 +244,13 @@ bool Polygon::isPartOfPolylineInPolygon(const Polyline& ply) const
 }
 
 bool Polygon::getNextIntersectionPointPolygonLine(
-    GeoLib::LineSegment const& seg, GeoLib::Point & intersection,
+    GeoLib::LineSegment const& seg, GeoLib::Point& intersection_pnt,
     std::size_t& seg_num) const
 {
     if (_simple_polygon_list.size() == 1) {
         for (auto seg_it(begin()+seg_num); seg_it != end(); ++seg_it) {
-            if (GeoLib::lineSegmentIntersect(*seg_it, seg, intersection)) {
+            if (GeoLib::lineSegmentIntersect(*seg_it, seg, intersection_pnt))
+            {
                 seg_num = seg_it.getSegmentNumber();
                 return true;
             }
@@ -260,7 +261,9 @@ bool Polygon::getNextIntersectionPointPolygonLine(
             for (auto seg_it(polygon->begin()); seg_it != polygon->end();
                  ++seg_it)
             {
-                if (GeoLib::lineSegmentIntersect(*seg_it, seg, intersection)) {
+                if (GeoLib::lineSegmentIntersect(*seg_it, seg,
+                                                 intersection_pnt))
+                {
                     seg_num = seg_it.getSegmentNumber();
                     return true;
                 }
diff --git a/GeoLib/QuadTree.h b/GeoLib/QuadTree.h
index b9cbdef9563dbbee13ab5b7a2892917f8755ca43..f61095755da3c19e92b9d01bc9ad13a7451595a9 100644
--- a/GeoLib/QuadTree.h
+++ b/GeoLib/QuadTree.h
@@ -54,18 +54,10 @@ public:
         : _father(nullptr),
           _ll(std::move(ll)),
           _ur(std::move(ur)),
-          _depth(0),
-          _is_leaf(true),
           _max_points_per_leaf(max_points_per_leaf)
     {
         assert (_max_points_per_leaf > 0);
 
-        // init children
-        for (auto& child : _children)
-        {
-            child = nullptr;
-        }
-
         if ((_ur[0] - _ll[0]) > (_ur[1] - _ll[1]))
         {
             _ur[1] = _ll[1] + _ur[0] - _ll[0];
@@ -508,14 +500,8 @@ private:
           _ll(std::move(ll)),
           _ur(std::move(ur)),
           _depth(depth),
-          _is_leaf(true),
           _max_points_per_leaf(max_points_per_leaf)
     {
-        // init children
-        for (auto& child : _children)
-        {
-            child = nullptr;
-        }
     }
 
     void splitNode ()
@@ -643,7 +629,8 @@ private:
      *   _children[2] is south west child
      *   _children[3] is south east child
      */
-    QuadTree<POINT>* _children[4];
+    std::array<QuadTree<POINT>*, 4> _children = {nullptr, nullptr, nullptr,
+                                                 nullptr};
     /**
      * lower left point of the square
      */
@@ -652,9 +639,9 @@ private:
      * upper right point of the square
      */
     POINT _ur;
-    std::size_t _depth;
+    std::size_t _depth = 0;
     std::vector<POINT const*> _pnts;
-    bool _is_leaf;
+    bool _is_leaf = true;
     /**
      * maximum number of points per leaf
      */
diff --git a/GeoLib/SurfaceGrid.cpp b/GeoLib/SurfaceGrid.cpp
index 85992e8a028d014bc3e7ae056dbc831eb24f7d93..3f66c58e6ad2f9113c395a160936924f62e56ea6 100644
--- a/GeoLib/SurfaceGrid.cpp
+++ b/GeoLib/SurfaceGrid.cpp
@@ -201,9 +201,11 @@ SurfaceGrid::getGridCellCoordinates(MathLib::Point3d const& p) const
     return boost::optional<std::array<std::size_t, 3>>(coords);
 }
 
-bool SurfaceGrid::isPointInSurface(MathLib::Point3d const& p, double eps) const
+bool SurfaceGrid::isPointInSurface(MathLib::Point3d const& pnt,
+                                   double eps) const
 {
-    boost::optional<std::array<std::size_t,3>> optional_c(getGridCellCoordinates(p));
+    boost::optional<std::array<std::size_t, 3>> optional_c(
+        getGridCellCoordinates(pnt));
     if (!optional_c) {
         return false;
     }
@@ -211,15 +213,11 @@ bool SurfaceGrid::isPointInSurface(MathLib::Point3d const& p, double eps) const
 
     std::size_t const grid_cell_idx(c[0]+c[1]*_n_steps[0]+c[2]*_n_steps[0]*_n_steps[1]);
     std::vector<Triangle const*> const& triangles(_triangles_in_grid_box[grid_cell_idx]);
-    bool nfound(true);
-    const std::size_t n_triangles(triangles.size());
-    for (std::size_t k(0); k < n_triangles && nfound; k++) {
-        if (triangles[k]->containsPoint(p, eps)) {
-            nfound = false;
-        }
-    }
-
-    return !nfound;
+    auto const it = std::find_if(triangles.begin(), triangles.end(),
+                                 [eps, pnt](auto const* triangle) {
+                                     return triangle->containsPoint(pnt, eps);
+                                 });
+    return it != triangles.end();
 }
 
 } // end namespace GeoLib
diff --git a/MeshLib/MeshEditing/Mesh2MeshPropertyInterpolation.h b/MeshLib/MeshEditing/Mesh2MeshPropertyInterpolation.h
index 456ced78ac2008fa1b02315541babb5754d1cbc2..a21574193217575c0e3d54a44c55c7083d44c02e 100644
--- a/MeshLib/MeshEditing/Mesh2MeshPropertyInterpolation.h
+++ b/MeshLib/MeshEditing/Mesh2MeshPropertyInterpolation.h
@@ -41,11 +41,11 @@ public:
     /**
      * Calculates entries for the property vector and sets appropriate indices
      * in the mesh elements.
-     * @param mesh the mesh the property information will be calculated and set
-     * via weighted interpolation
+     * @param dest_mesh the mesh the property information will be calculated and
+     * set via weighted interpolation
      * @return true if the operation was successful, false on error
      */
-    bool setPropertiesForMesh(Mesh& mesh) const;
+    bool setPropertiesForMesh(Mesh& dest_mesh) const;
 
 private:
     /**
diff --git a/MeshLib/MeshSearch/MeshElementGrid.cpp b/MeshLib/MeshSearch/MeshElementGrid.cpp
index 8e45f5c60fc54f1fa326ab6fc7044abd36ed76f0..0aa33c7554d144958547a50a731861ce8151b4d1 100644
--- a/MeshLib/MeshSearch/MeshElementGrid.cpp
+++ b/MeshLib/MeshSearch/MeshElementGrid.cpp
@@ -21,11 +21,11 @@
 
 #include "GeoLib/GEOObjects.h"
 
-namespace MeshLib {
-
-MeshElementGrid::MeshElementGrid(MeshLib::Mesh const& sfc_mesh) :
-    _aabb{sfc_mesh.getNodes().cbegin(), sfc_mesh.getNodes().cend()},
-    _n_steps({{1,1,1}})
+namespace MeshLib
+{
+MeshElementGrid::MeshElementGrid(MeshLib::Mesh const& mesh)
+    : _aabb{mesh.getNodes().cbegin(), mesh.getNodes().cend()},
+      _n_steps({{1, 1, 1}})
 {
     auto getDimensions =
         [](MathLib::Point3d const& min, MathLib::Point3d const& max)
@@ -49,7 +49,7 @@ MeshElementGrid::MeshElementGrid(MeshLib::Mesh const& sfc_mesh) :
     std::array<double, 3> delta{{ max_pnt[0] - min_pnt[0],
         max_pnt[1] - min_pnt[1], max_pnt[2] - min_pnt[2] }};
 
-    const std::size_t n_eles(sfc_mesh.getNumberOfElements());
+    const std::size_t n_eles(mesh.getNumberOfElements());
     const std::size_t n_eles_per_cell(100);
 
     // *** condition: n_eles / n_cells < n_eles_per_cell
@@ -98,7 +98,7 @@ MeshElementGrid::MeshElementGrid(MeshLib::Mesh const& sfc_mesh) :
     }
 
     _elements_in_grid_box.resize(_n_steps[0]*_n_steps[1]*_n_steps[2]);
-    sortElementsInGridCells(sfc_mesh);
+    sortElementsInGridCells(mesh);
 }
 
 MathLib::Point3d const& MeshElementGrid::getMinPoint() const
@@ -111,9 +111,10 @@ MathLib::Point3d const& MeshElementGrid::getMaxPoint() const
     return _aabb.getMaxPoint();
 }
 
-void MeshElementGrid::sortElementsInGridCells(MeshLib::Mesh const& sfc_mesh)
+void MeshElementGrid::sortElementsInGridCells(MeshLib::Mesh const& mesh)
 {
-    for (auto const element : sfc_mesh.getElements()) {
+    for (auto const element : mesh.getElements())
+    {
         if (! sortElementInGridCells(*element)) {
             OGS_FATAL("Sorting element (id={:d}) into mesh element grid.",
                       element->getID());
diff --git a/MeshLib/MeshSearch/MeshElementGrid.h b/MeshLib/MeshSearch/MeshElementGrid.h
index caae5852840bce90d50641432eb640e438be3bcb..bd546ffee627db920d944a78963c9a250d03b607 100644
--- a/MeshLib/MeshSearch/MeshElementGrid.h
+++ b/MeshLib/MeshSearch/MeshElementGrid.h
@@ -75,7 +75,7 @@ public:
     MathLib::Point3d const& getMaxPoint() const;
 
 private:
-    void sortElementsInGridCells(MeshLib::Mesh const& sfc_mesh);
+    void sortElementsInGridCells(MeshLib::Mesh const& mesh);
     bool sortElementInGridCells(MeshLib::Element const& element);
 
     GeoLib::AABB _aabb;
diff --git a/ProcessLib/GroundwaterFlow/CMakeLists.txt b/ProcessLib/GroundwaterFlow/CMakeLists.txt
deleted file mode 100644
index ec13ffc725965b9eedfe4c4882a52a334ad132eb..0000000000000000000000000000000000000000
--- a/ProcessLib/GroundwaterFlow/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-append_source_files(SOURCES)
-
-ogs_add_library(GroundwaterFlow ${SOURCES})
-
-target_link_libraries(GroundwaterFlow PUBLIC ProcessLib PRIVATE ParameterLib)
-
-if(BUILD_TESTING)
-    include(Tests.cmake)
-endif()